Social bookmarking is a web-based service, where shared lists of user-created Internet bookmarks are displayed. Social bookmarking sites generally organize their content using tags. Social bookmarking sites are an increasingly popular way to locate, classify, rank, and share Internet resources through the practice of tagging and inferences drawn from grouping and analysis of tags. In a social bookmarking system, users store lists of Internet resources, which they find useful. Often, these lists are publicly accessible, and other people with similar interests can view the links by category, tags, or even randomly. Some social bookmarking systems allow for privacy on a per-bookmark basis.
Web 2.0 is part of the community and vice versa. Social bookmarking is part of it, too.
This system has several advantages over traditional automated resource location and classification software, such as search engine spiders. All tag-based classification of Internet resources (such as websites) is done by human beings, who understand the content of the resource, as opposed to software which algorithmically attempts to determine the meaning of a resource. This provides for semantically classified tags, which are hard to find with contemporary search engines.