Monday, February 4, 2008


Social bookmarking is a method for Internet users to store, organize, search, and manage bookmarks of web pages on the Internet with the help of metadata.

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. The allowed people can usually view these bookmarks chronologically, by category or tags, or via a search engine.

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. They also enable viewing bookmarks associated with a chosen tag, and include information about the number of users who have bookmarked them. Some social bookmarking services also draw inferences from the relationship of tags to create clusters of tags or bookmarks.

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.

The concept of shared online bookmarks dates back to April 1996 with the launch of Within the next three years, online bookmark services became competitive, with venture-backed companies like Backflip, Blink, Clip2, Hotlinks, Quiver, and others entering the market. Lacking viable models for making money, this early generation of social bookmarking companies failed as the dot-com bubble burst.

Founded in late 2003, pioneered tagging and coined the term "social bookmarking". In 2004, as began to take off, Citeulike, Connotea (focusing on social bookmarking for scientists), Simpy, Furl, and Stumbleupon were released, and Netvouz in 2005. In 2006, Ma.gnolia and Diigo also entered the bookmarking field. Sites such as Digg, reddit, and Newsvine are a related type of web service that provides a system for social news. In 2006, Connectbeam was the first company to launch a social bookmarking application squarely focused at businesses and enterprises, and continues to innovate in this direction. In 2007, IBM announced plans to enter the social software market, and the BBC web site added social bookmarking links for its news and sport articles, as many other news websites had done earlier.

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 web sites) 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.

Additionally, as people bookmark resources that they find useful, resources that are of more use are bookmarked by more users. Thus, such a system will "rank" a resource based on its perceived utility. This is arguably a more useful metric for end users than other systems which rank resources based on the number of external links pointing to it.

There are drawbacks to such tag-based systems as well: no standard set of keywords (also known as controlled vocabulary), no standard for the structure of such tags (e.g. singular vs. plural, capitalization, etc.), mistagging due to spelling errors, tags that can have more than one meaning, unclear tags due to synonym/antonym confusion, highly unorthodox and "personalized" tag schemas from some users, and no mechanism for users to indicate hierarchical relationships between tags (e.g. a site might be labeled as both cheese and cheddar, with no mechanism that might indicate that cheddar is a refinement or sub-class of cheese). Services which allow both tags and folders for organizing bookmarks (such as Netvouz) make this less of a problem though.

Social bookmarking can also be susceptible to corruption and collusion. Due to its popularity, some users have started considering it as a tool to use along with Search engine optimization to make their website more visible. The more often a web page is submitted and tagged, the better chance it has of being found. Spammers have started bookmarking the same web page multiple times and/or tagging each page of their web site using a lot of popular tags, hence obliging the developers to constantly adjust their security system to overcome abuses. Because of this, some social bookmarking websites were forced to add CAPTCHA protection against spam, which caused some problems for people who use social bookmarking for non-spamming purposes.