A bookmark site, del.icio.us, allows users to organize their web bookmarks online and access saved links from any Internet-connected computer. del.icio.us, acquired in December 2005 by Yahoo!, is also a social bookmarking site because users can index and share their webpages with other people. The site also lets users find other people who have interesting bookmarks and add those sites to their own saved links. The difference between a web browser and del.icio.us is that the latter does not use bookmark folders. Users of del.icio.us use a tag to describe a saved link, and can use as many tags as they need. This tagging method is an illustration of a user-generated classification method, called folksonomy, which is builds up a body of information that makes it progressively simpler and effortless to search and discover interesting links at del.icio.us. Registration is not a requirement to see the interesting links that other users have saved on the site. Users are asked to register if they want to store their saved webpages on del.icio.us. The home page features a hotlist, which shows the webpages recently bookmarked by other user. The tags to watch feature a list of the most popular tags used on the site. del.icio.us also features a search engine, which displays search results based on Boleean queries, as well as the XOR operator. Bookmarks are set on private by default, so users who may prefer not to share their bookmarks with other users can do so.