It really depends on what you need. As of the moment, however, the most popular online promotion is Facebook Marketing.
Facebook is the most popular social networking site in which you can promote your site by creating and updating your business page. You can manually post contents and links in the page but for better promotion, consider using Facebook Ads.
The Facebook Ad is a paid marketing technique in which your page appears in Facebook sidebar. Chances are, more people will see and will LIKE the page and each time you make an update, it appears in their timeline and if they are interested, people might like your post and will visit the link you just posted.
This post has been edited by Dennis Montgomery: Oct 8 2013, 08:58 AM