As you know seo is very important nowadays. Seo is not just optimization. 2 months ago Google change their crawling technique and now they use Google Caffeine. In this technique social bookmarks are very important. Social bookmarks are very populer right now and if you won't use it's silly. After post or update something on you weblogs add it to social bookmarks like Twitter, StumbleUpon, Digg, Reddit, Technorati, Yahoo Buzz, Google Buzz, Delicious, Slashdot, Friendfeed, Newsvine, Diigo, Mister Wong, Dzone, Faves ...etc.
There are to many social bookmarks in web. You can find them easly on Google or if you use Wordpress or something like that there are plugins for social bookmarking. Use one of them.
With social bookmarking use website is indexing by search engines, you got many visitors and hits. Especially I'm suggesting to you StumbleUpon. It's amazing. I post an article and I've 200+ visitors via StumbleUpon.