Social bookmarking isn't new, but only in recent years (at least partially as a result of becoming favored with search engines) has social bookmarking become so popular. For sites looking to achieve search engine results, social bookmarking is a great way to increase exposure and search engine positioning.

Why Search Engines Like Social Bookmarks
Search engines - especially Google - are always looking to index new and relevant content while at the same time trying to distinguish between sites of quality and those that are just trying to achieve first page ranking; this is a particularly tough challenge for a search engine spider that doesn't view content cognitively. Social bookmarks are a way for users to select what is important to them by bookmarking the sites publicly. Many social bookmarking sites further distinguish quality of the sites by allowing rating of the bookmarks. Since these users are the target market of search engines, it makes sense to correlate, at least to some degree, the results of these social bookmarks into the search engine algorithms, and because social bookmarks are often new and relevant, pages linked from them often achieve first page rankings in a matter of hours or days instead of weeks or months.

Getting Started
We created an x-cart mod, Social Bookmarks for X-Cart, which can have your x-cart setup with social bookmarks in 5-10 minutes.