Social bookmarking sites are very popular. Bookmarking sites are important especially for bloggers to improve seo and helps your site to be in top sites on search engine rankings. Search engines calculate book marks as votes and use tags for finding data related to query. Bookmarking also allows you to get backlinks and get traffic.

Social bookmarking sites also allow you to build networks, interact with people of similar interest, get news of your interest area via subscribing. To get all this you need to get a free account at these sites and try these sites for some time. Get your friends to vote and increase ranking in search results
Best bookmarking sites include stumbleupon, del.icio.us, digg, reddit and technorati. To make it easier for readers to bookmark your site you can add social book mark option below your blog post.