Regarding structure and organization of knowledge, the Web is the realization of the hypertext (or hypermedia) model. Non-linear structure, complex linkage within and between information units, and appropriate navigation and search tools are defining features of this model. Our results reveal only a shallow presence of these features in the evaluated Websites (Table 3). Only about half of the sites included within-the-site linkage to a reasonable extent (more than one link per page), and about 11% of the sites refer to other sites (external linkage) at the same extent.

Table 3: Link structure in educational Websites

	Not at all	At list one in the site	50% of pages in the site		One per page	More than one
Within the site	116 (26.6%)	32 (7.3%)	20 (4.6%)		50 (11.5%)	218 (50.0%)
Links to external sites	253 (58.0%)	68 (15.6%)	37 (8.5%)		32 (7.3%)	46 (10.6%)
LINKS TO:	Yes (N of sites %)			No (N of sites %)
external databases	74 (17.0%)			362 (83.0%)
external tools	12 (2.8%)			424 (97.2%)
external activities	42 (9.6%)			394 (90.4%)
virtual reality devices	8 (1.8%)			428 (98.2%)
human communication	25 (5.7%)			411 (94.3%)

Communications

The results of this study show that limited communication resources were used in most Websites (Table 4). The most (and almost sole) resource present in the sites is electronic mail (about 65% of the sites). Other tools such as discussion groups, chat, or any form of distant work (e.g., tele-manipulation, tele-creation) were found only in a few sites. Moreover, features aimed to support working groups or learning communities were not found in any of the evaluated sites. The gap betweenÜexpectations and actual implementation in the communications domain is even more evident than in the previously discussed domains. The main reason for that is that the technological resources do exist and are being successfully implemented in other areas of peopleís life (e.g., work, professional training, banking, shopping). In addition, transactions among humans and between humans and information resources are quintessential to education, and it is not hard to conceive endless forms of support that communication technology could offer for these processes. As for todayís reality, this support is not yet a function in most educational Websites.

Table 4: Use of communication resources in Websites

	Yes (N of sites, %)
Synchronic activities	17 (3.9%)
Communication means
e-mail	283 (64.9%)
Discussion group without mediator	15 (3.4%)
Discussion group with mediator	10 (2.3%)
Chat	8 (1.8%)
Moo/mud	0 (0%)
Video conference	0 (0%)
Tele-manipulation	1 (0.2%)
Tele-creation	7 (1.6%)

CONCLUSIONS

In a previous paper we characterized the first stages in the assimilation process of every new technology by educators as ìone step ahead for the technology, two steps back for the pedagogyî (Mioduser, Nachmias, Oren, & Lahav, in press). As experienced educatorsÜwe hold substantial models regarding the varied facets of our practice (e.g., how to build a lesson plan, to assess a learnerís performance or behavior, to develop a learning unit). These models are usually tied to the (technological) resources at hand, and they affect each other mutually. It seems reasonable to assume that when facing the assimilation of a new technology we use these models as input to the process. The result is usually a transition period at which we replicate the known models by means of the new technology. While first assimilating the computer technology developers replicated the programmed instruction paradigm by means of the new technology, initially in the form of electronic worksheets and booklets then evolving in time into sophisticated drill and practice and structured tutoring software (Venezky & Osin, 1991). Our claim is that this study reveals a similar transitional phenomenon regarding the vast majority of educational Websites. Most sitesí main component is the information-base, built upon the hypermedia-CD model (even a feature with can be claimed as unique to the Web, as the linkage to external sites, is today included in many hybrid CD-Web products). As for interactivity features based on the implementation of new technological resources (e.g., forms, Java applets, Shockwave), most online activities resemble the automatic-feedback (behaviorist-like) transactions of classic CAI (e.g., multiple-choice, select-correct-part, assemble-correct-configuration).

In light of these results one can adopt the skepticsí perspective and argue that Web technology has little to offer to education. But one can also adopt a more thoughtful perspective, reflecting on the potential outcomes of this transition stage and looking for unique examples of emerging (and promising) directions in the research and development of educational Websites. In the following we will briefly refer to five such relevant directions.

Curricular issues

A great deal of theoretical and practical knowledge has been generated regarding curriculum research and development based on the print technology (e.g., see the definitely classic by Tyler, 1949, or the comprehensive review in Jackson, 1992). The shift towards representing and delivering knowledge by means of digital technology (side-by-side with the textbook? Instead of the textbook?) is today an unquestionable reality. This shift represents profound changes regarding key curricular issues, for example:

• curricular resources (e.g., from limited-media to multimedia)
• knowledge organization (e.g., from linear and hierarchical structure to web-like and multiple layers structure)
• locus of responsibility for the creation of significant curricular packages (e.g., from developer/teacher generation of structured learning units to learnersí personal curriculum and ad-hoc chunking of knowledge units)

These and other changes create the need to revise current curricular theories. Considering the principles underlying the print-technology-curriculum versus the digital-technology-curriculum, how can we relate the later to the former: natural continuation? gradual evolution? break through? The preliminary answers embodied in current quality Websites are more instances of pragmatic decision-making than of theoretical formulation of new curricular principles. The challenge is thus twofold. First, we should identify, analyze, categorize and generalize these pragmatic solutions as first step in the definition of a more general body of curricular principles. But at the same time we should elaborate, focusing on the unique characteristics of the new technology, on new directions and models which appear to be promising for supporting innovative teaching and learning processes.

Among the Websites that exemplify new curricular trends a salient representative is Chickscope (http://chickscope.beckman.uiuc.edu/) - initiated by educators and researchers from several departments at the University of Illinois at Urbana-Champaign.The website offers students and teachers the opportunity to access updated scientific data. Using the Internet students and teachers can login to computers at the university that controlls a Magnetic Resonance Imaging (MRI) system, manipulate experimental conditions through a simple Web interface to generate their own data, and view the resulting MRI of the chick embryo in real time. In addition, this Website includes: a day-by-day multimedia journey through the life-cycle of a chicken embryonic development; a series ofÜinteractive activities demonstrating mathematical properties of Embryology; a course in Biological imaging and image processing; and a large database of MRI. Teachers and students have full responsibility in creating their own learning program, communicating with researchers at the university, and with friends to reflect on their learning.

Several Websites also provide web-based tools to scaffold knowledge integration. For example, the WISE curriculum project (http://wise.berkeley.edu/WISE/index.html) offers a Web-based learning environment where students perform innovative science curriculum activities that draw from the wealth of material available on the Internet. These activities can vary widely, including: Survey existing Web material; perform a handson (off-line) activity; participate in an electronic discussion; critique other classmates' designs; etc. A detailed description can be found in Linn and Hsi (1999).

Collaborative Learning

Undoubtedly one of the defining features of the Web technology is that it enables peoples interaction with (distant repositories of) knowledge as well as with each other - namely communication. These two within-group events, knowledge manipulation and interpersonal transactions, were extensively studied in the contextÜof group learning processes (e.g., Sharan, etc.). However, in the context of the new technologies we should pay attention to significant changes in group functioning in contrast to traditional group learning situations, among others:

• The group functioning is not limited by place or time boundaries. The usual face-to-face and simultaneous action characterising group work does not longer exist.
• Members can assume varied roles and even (in less formally defined situations) varied identities according to changing situations.
• Interpersonal transactions are mediated by the technology (e.g., massive use of writing and other symbolic resources).
• In many occasions (asynchronous work), the membersí participation is generated in differentiated stages also separated in time: elaboration, delivery, and feedback recollection stages. A crucial implication is that the memberís contribution to the groups work can be elaborated beforehand, without the pressure or timing demands of real-time face-to-face communication situation.

Examples of Websites supporting collaborative activities are: GLOBE (http://www.globe.gov/) - a worldwide network of students, teachers, and scientists working together to study and understand the global environment by creating and investigating collaborative database; Educational MOOs (see a comprehensive list in the recent book of Haynes & Holmevik, 1998); ThinkQuest (http://www.Thinkquest.org/tq/) which is an interactive, collaborative gaming environment.

Learning Communities

Computer mediated communication (CMC) is a key resource for the creation of learning communities. A learning community can be defined as a novel educational system based on the combination of three components (Oren, Nachmias, Mioduser, & Lahav, in press): a virtual community (social dimension), hosted by an appropriate virtual environment (technological dimension), and embodying advanced pedagogical ideas (educational dimension).

Many sites on the Internet define themselves as virtual learning environments, in the most general sense: a gateway to information and communication, any time and from any place. However, a more detailed analysis of such sites reveals that they do not possess all the features that are essential for a virtual environment to support a virtual community aimed at learning, e.g.,:

• Most of them do not present the building of a community as a goal.
• Many of them do not stand independently, but rather function as supplements of real institutions.
• Their environment does not motivate social immersion.
• They do not offer multi-user situations, even if they use common communication means.
• They lack pedagogical features which are essential for creating a learning community.

If virtual learning communities are offered as a third place in addition to work or school, and to home (Oldenburg, 1991), they should be developed upon novel conceptions and offer unique tools and activity modes, which differentiates them from the other spaces. This environment should supply all the communicational tools needed for developing social relations, tutor-student relations, and expert-novice relations. Likewise, management and moderating functions should be included to support social definitions (e.g., status, roles) and transactions. These environments should promote learning processes based on membersí personal interests, willingness to participate, and motivation to interact with peers, teachers and other knowledge sources within a dynamic learning community.

MATAR (http://www.matar.ac.il/) as a national science and technology virtual learning community for teachers, provide a good example for these ideas. MATAR seeks for ways to involve elementary school science and technology teachers in the virtual community providing them on-line usefulÜinformation, virtual courses, and opportunities to communicate. Another example of learning community appears in the Teachers Helping Teachers site (http://www.pacificnet.net/~mandel/).ÜThis Website provides basic teaching tips to inexperienced teachers; new ideas in teaching methodologies for all teachers and a forum for experienced teachers to share their expertise with colleagues around the world.

Visual languages

The use of visual materials to represent aspects of the world, ideas, and emotions has been an essential component of human's experience since the beginning of humankind. From the very first visual creations on the cave walls and peopleís own bodies, to the current digital virtual worlds, visual materials fulfil a variety of roles in our lives, e.g., communication, education, expression. For several centuries however, the written and printed word have been the main conveyors of information, and the main representational means serving educational purposes as well (Baron, 1997). During this period, images were incorporated in texts mainly for illustration or for ornamental purposes. In this century, image-based technologies (e.g., cinema, television), and more recently digital multimedia, brought visual representations back into the centre ofÜthe scene with unprecedented strength. Educational Websites play an active role within this trend, adopting as well as contributing to the development of a variety of salient features, such as:

• Visual materials recovered their function as self-sufficient educational and communication agents. In pre-literate cultures, visual materials played a unique role in the transmission of information and values (e.g., as in he immersive environments of frescoes-saturated churchs). Due to the dominant position of the text in the print technology, images were relegated to a complementary or support role. With the digital technology, visual materials' status as self-contained units was renewed, but now in more complex and sophisticated ways than in previous cycles, asÜexemplified in the following items.
• Comprehensive symbol systems for learning and working within digital environments have been developed on the basis of visual materials. These developments include the informal consolidation of conventions as part of the Internet evolving culture (e.g., the adoption of shared conventions in e-mail and chat environments such as the symbol ": )", or in the design of icons for common functions in Web pages), as well as the formal definition of complete visual languages for accomplishing programming or design tasks.
• The representational resources repertoire is expanding. Visual materials are no longer restricted to still images. Alternative representational forms (e.g., static, dynamic, 2D, 3D, pre-made or rendered in real-time) allow learners to deal with additional ways of accessing information other than decoding it from still images (e.g., use of scientific visualization tools with real-time data, acting virtually within immersive environments). These alternative forms also contribute dynamic and interactive dimensions to the digital learning environments.
• Cognitive processes based on the use of visual raw materials are encouraged, promoting new forms of visual reasoning (e.g., mental modeling of processes, reasoning with visual metaphors).
• The communication resources universe for Learning disabled persons expands. Visual materials, metaphors and languages enable people to use alternative channels (besides the text-only and formal-analytical-only characteristic of the print technology) for learning and working.

Several websites support visual languages, by using icons, 2D & 3D images, VRMLs, interactive images and complex visual representations. For example: The Alphabet Superhighway (http://www.ash.udel.edu/ash/) use rich visual resources supporting the creation, location, and communication of information by students through active learning, guided discovery, mentoring, competitions, and other on-line activities.

Knowmagine - A Virtual KnowledgeÜParkÜof Science, Technology, and Human CultureÜÆhttp://www.tau.ac.il/~museum/kc-muse.html) includes static, dynamic, 2D and 3D interactive images.

The site of Blossoms of Science at the Jordan Valley College (http://www.yarden.ac.il/bloss/newbloss/engbloss.htm), provides opportunity for students to use a modern optical telescope at the observatory to view changing real-time maps. Complex visual representations can be viewed in the Science Learning Network resources such as: Hurricane Spiral maps, ocean maps and visual weather maps (http://www.sln.org).

Distance learning

Web technology has contributed to the creation of new forms of distance learning, either by empowering existing resources of traditional distance education or by the creation of new resources. For example, in contrast to the traditional one-way and one-to-many traditional TV broadcasting of lectures, video conferencing represent a significant switch towards multiple-ways participation and many-to-many interactivity. A dominant form in the development of Web-based distance learning are virtual courses. Their number is continuously growing, andÜappear in a wide range of configurations. At one end a large number of isolated courses can be found on a large diversity of topics. At the other end are organized virtual schools of different types (e.g., secondary, vocational, university) proposing many courses, and even offering formal acreditation and degrees. This study focused mainly on WBLEs in general, and not specifically on virtual courses ó however in many cases the distinction was difficult to make. A number of salient issues in this evolving trend are mentioned in the following.

• The idea of a "global school", namely, the courses can be reached from everywhere, at any time, in unlimited number of subjects (at least potentially, depending on pace of development and demand). School space, time, organization and formal curriculum are no longer constraints for people's decision making about the configuration of their own learning.
• Ample range of instructional bundles can be found, from open ended repositories of information complemented with sets of worksheets and/or focused task briefs, to highly structured online courses.
• Extensive range of topics are dealt with, including highly specific or rare topics, and the interaction with experts and lecturers which could not be expected to be available otherwise in traditional learning settings.
• Asynchronic interactions confer unique characteristics to learning transactions. For example, traditional group discussions usually confined in time and space, gain new dimensions, e.g., the discussion evolve in time and proceed through cycles; the participants have the opportunity to reflect on their own and others' contributions; participants have the opportunity to contribute at their own pace and decision, and every contribution is registered and reach all others; an increase in amount and diversification in type of partners takes place.
• There is a real opportunity to harness the new technological tools in pursue of long life learning objectives, offering different populations a variety of learning opportunities according to their desires and needs.

The Virtual High School (VHS) project (http://vhs.concord.org/) is a joint effort of high schools from all over the USA. All the participating schools have access to a vast repositoire of online, exciting, high-quality courses, gain greater flexibility in teaching assignments, and offer students exposure to students from other backgrounds and cultures (Tinker, 1998). More online K -12 virtual schools and courses can be found in (http://www.wested.org/tie/dlrn/k12courses.html).

The authors are part of the community of educators dealing with the problematic involved in the assimilation of Web technology to education (Mioduser & Oren, 1998; Nachmias, Mioduser, Oren & Lahav, in press). Although in this study we have referred to the educational Websites population in quantitative terms, we are aware that a number of fascinating examples of high pedagogical-quality sites do exist in the Web. But our main purpose in this study, rather to focus on the exceptions, was to map and learn what most existing sites and current trends as they are delivered to cyberspace have to offer to educators and learners. Based on this and similar studies, the next steps should focus on the research and development of novel Web-based educational models (Windschite, 1998) and on the implementation of a revised configuration of the technology-assimilation evolutionary loop: two steps ahead for the pedagogy/technology, one step back for reflection and mindful planning of subsequent steps.

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