Social media site advertising agency?

With reference to Nikolas's great social bookmarking site tutorial (http://www.webdigity.com/index.php/topic,6758.0.Social+bookmarks+-+Let%27s+make+a+tutorial+on+that.html), I decided to ask if you can share some experience about companies that can do advertising social media sites. Someone who can do that professionally...

You mean a company that can submit your content to social media sites, or a company that can advice you how to have more social media optimized content?

I mean the company which would promote me in social media. Not just submitting... I mean really quality campaign: learning our audience, optimizing (if necessary our content for social media, e.g. I heard headlines are really important for those sites), submitting, etc...

That's a task for a SEO company

Yeah, I understand that. I just thought with that social boost, there should be some social-media-specific companies which would handle all the campaign and if necessary - video advertising in video social networks.

I think it is more like SEO companies are transforming the way the web is :)