* Only when your social bookmarking sites use ‘do follow’ attribute, search engines will be able to follow the links and give credit to that link. In other words, your link will be counted only when it comes from a page with ‘do follow’ attribute.
* Second important factor that you should take into consideration is the reputation or popularity of the social bookmarking site.Social bookmarking sites with good visitor traffic will be a good source of traffic to your website.