social bookmarking definitely attracts a lot of traffic to your site and is beneficial for your rankings also.
You will have to go for article submissions, press release distributions, and social bookmarking as well.
Social media is an umbrella term that includes interactive broadcasts such as blogs and podcasts, as well as social networking Web sites. These Web sites often allow visitors to become users or members, create profiles, and upload and share content through the Web site. There are hundreds--if not thousands--of social media Web sites out there, but here are a few of the more popular ones: Twitter, Facebook, Space & Linkedin websites one of the fastest growing social media sites out there. It started as a site just for college students but is now open to everyone. Although it has fewer members than MySpace, its growth and buzz is enough to make Google nervous.
Yah...we are also doing article submission in our company. it helps a lot in getting good backlinks. But not excessive submissions.