Social bookmarking sites, are sites that allow users to post their favorite sites, using tags (or keywords) to categorize and organize them; then other users can take these bookmarks and add them to their own collection or share them with even more users.
Social bookmarking is a method for Internet users to share, organize, search, and manage bookmarks of web resources. Unlike file sharing, the resources themselves aren’t shared, merely bookmarks that reference them.
Descriptions may be added to these bookmarks in the form of metadata, so that other users may understand the content of the resource without first needing to download it for themselves. Folksonomy is also called social tagging, “the process by which many users add metadata in the form of keywords to shared content”.
In a social bookmarking system, users save links to web pages that they want to remember and/or share. These bookmarks are usually public, and can be saved privately, shared only with specified people or groups, shared only inside certain networks, or another combination of public and private domains.
Most social bookmark services encourage users to organize their bookmarks with informal tags instead of the traditional browser-based system of folders, although some services feature categories/folders or a combination of folders and tags.
Many social bookmarking services provide web feeds for their lists of bookmarks, including lists organized by tags. This allows subscribers to become aware of new bookmarks as they are saved, shared, and tagged by other users.
As these services have matured and grown more popular, they have added extra features such as ratings and comments on bookmarks, the ability to import and export bookmarks from browsers, emailing of bookmarks, web annotation, and groups or other social network features.