Google's starred-search (if that's what it's called) might be characterized as instant bookmarking. I've written in the past that searching through our bookmarks is probably more complicated than simply running a new search, so why not remove the middle step of actually tagging a page with a distinct tag and adding it into our ever-growing list of bookmarks, and simply make it instantly identifiable in a list of search results. Which seems to be precisely what Google has done.
Run a search, find something you'll want to find again, and click on the empty star. From now on it will be yellow, and will appear that way, and at the top of the results page, for every future search we conduct on the same search term:
No need to remember a URL, no need to ask "where was that page again?". Search ... and Google will remember for us.
