Social bookmarking is an activity performed over a computer network that allows users to save and categorize (see folksonomy) a personal collection of bookmarks and share them with others. Users may also take bookmarks saved by others and add them to their own collection, as well as to subscribe to the lists of others. – a personal knowledge management tool. Although using social bookmarking growing in popularity one should consider the threat to privacywhen using these services. This new part of the web started around late 2003, when del.icio.us was launched. It quickly gained popularity, many similar services appeared online, tagging became widespread in some other online services. In mid-2005, with the launch of My Web 1.0 BETA by Yahoo! the practice of social bookmarking moved much closer to mainstream. Drawbacks of current implementations include: single word categories, although many services allow multi-words to be enclosed in inverted commas, no mechanism to define or refine categories, no synonym/antonym control or related terms and no hierarchy. A useful feature is RSS feeds per category (tag) that you can subscribe to – alerting you to new links in your areas of interest. This has been added to the tools section of Research Resources Subject Tracer Information Blog. This has been added to Social Informatics Subject Tracer Information Blog.