Wikipedia
CiteULike is a web service which allows users to save and share citations to academic papers. Based on the principle of social bookmarking, the site works to promote and to develop the sharing of scientific references amongst researchers. In the same way that it is possible to catalog web pages (with Furl and delicious) or photographs (with Flickr), scientists can share citation information using CiteULike. Richard Cameron developed CiteULike in November 2004 and in 2006 Oversity Ltd. was established to develop and support CiteULike.
When browsing issues of research journals, small scripts stored in bookmarks ( bookmarklets) allow one to import articles from repositories like PubMed, and CiteULike supports many more. Then the system attempts to determine the article metadata (title, authors, journal name, etc.) automatically. Users can organize their libraries with freely chosen tags and this produces a folksonomy of academic interests.