First things first, Social bookmarking site is a website where the users can manage their own bookmarks and share websites with a community of users. Del.icio.us, for one, is a famous social bookmarking site that boasts more than 3 million users. Also, one of the oldest social bookmarking sites that we have today is itlist.com, which was launched in 1996. However, bookmarking did not create big waves until last year.

Lots of Internet users have hundreds or perhaps thousands of items in their bookmark list. The latter helps them organize their fave web pages. However, the list is more than just an organizational tool; it means more to web search engine optimization. Why?

Major search engines rank web pages by relevance and quality score. Relevance score is calculated by on-page content and backlinks. On the one hand, quality score is calculated by links from other pages. The scheme is straightforward. It means that more quality links your page has, the better is your chance to rank high in search engine results. With 3 million sample, for instance, it is reasonable to say that social bookmarking sites are essential in the ranking algorithm.