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.
Facebook, Twitter, Google+, etc.(saving, starrng, etc. Gets unwieldy fast as there is no organizing except chronological)
Web Archiving - finding things no longer around; making sure stuff will be findable
(Instapaper and Pocket and Diigo can also keep text+images copies of webpages, although in some cases premium plans are required)
Why are these different?