Social bookmarking is the act of submitting updates of your website/articles into bookmarking websites. It's like sharing an interesting website/article to many other people. There are hundreds of bookmarking websites out there. These websites have high ranking in Google and high traffic every day. Thus bookmarking your website updates here will get yourself visible to more people. Try reddit.com for example, when you visit that site you will see many people bookmarking their websites or interesting sites they found. Social bookmarking is for 2 purpose: getting people click through your bookmarked link and visit your website, and at the same time to make your website visible to search engines like Google, thus to make your site indexed faster. On your website you can put adsense, affiliate links... and that's how you make money. Hope this helps