AddThis is a free easy to utilize web service that enables you to increase your site traffic by enabling visitors to easily bookmark and share your web pages and content with social networks such as Facebook, Twitter, and so many more. The service works by letting you add a customizable button to your site that contains all the popular sharing tools in one place, allowing the visitor to quickly link your content out into the web for others to enjoy.
In addition the AddThis team even has analytics enabled for registered users(free registration) that allows you to see what pages are getting bookmarked or shared and to what services. In the detailed articles found on my site you will see one of the possible formats for the AddThis button. If you have a website or blog that you want to increase traffic to, then this is a free tool/service that you would be well worth integrating.