Yahoo launched My Web, an extension to the Yahoo Toolbar that lets you save on Yahoo's servers a copy of any web page you've seen. The idea is that it lets you find web pages you saw once before quickly and easily.
This isn't quite like Seruku, which saves a copy of every web page you've seen on your own computer. Or quite like Google Desktop Search, which searches over every web page you've seen recently (using the browser cache on your computer). Or quite like Filangy, which (sort of) stores every page you've seen on their servers.
Because you have to explicitly push a button to save the page, I'm not sure how many people will use Yahoo My Web. Seems likely to me that, when I'm browsing a particular page, I don't really know if I'll want to find it again. It'll be too late when I decide I really should have pushed that little button.
Cute idea though. Fun to see all the innovation lately.
See also Chris Sherman's review of Yahoo My Web.
Update: Tony Gentile posts a detailed review. He also points out that Yahoo My Web probably should be considered more of a bookmarking tool than a step toward Memex.