Social bookmarking is a method for Internet users to store, organize, search, and manage links to Web pages they want to quickly access and share via tagging. These bookmarks can be private, completely public or shared only with specific people or groups, which is what makes the software social — unlike the links you have saved in your Internet browser.
Social bookmarking can be faster than using a search engine, but it has its own drawbacks. As this primer by the Educause Learning Initiative points out, social bookmarking is done by amateurs, which means they can be maddeningly inconsistent. If you’re searching for links tagged “medieval,” you’ll miss those tagged “mediaeval,” for example.
Still confused? Watch this explanatory video from Common Craft.