A social bookmarking tool that enables much more, including annotation, sharing, collaboration, image capturing/annotation, and web highlighting. Freemium options, but the free version is pretty good. Find my Diigo site at http://www.diigo.com/user/loenglish. Find Diigo Tools at https://www.diigo.com/tools and Diigo Help at http://help.diigo.com/. Also Diigo plans.
The Internet Archive now will occasionally come up when you hit a 404 (file not found) page: example Wordle.net
Why are these different?