Anyone has any "online marketing company" here?

I'm just curious to know if anyone has a company that handles the online marketing aspects of client companies. By that, I mean maintaining facebook pages, twitter accounts, video marketing, article marketing etc (everything except SEO).

Example, I have, let's say a company that sells orange juices. You are an online marketing company. I have a website but I don't know how to promote or don't have the expertise to promote. You tell me that you'll maintain fb, twitter, g+, video, article marketing for me and I'll pay you a monthly subscription fee. Would this work?

Sure it would work, but large companies will have their own in-house staff for that, and very small companies will just have the owner do it themselves usually. What you have to aim for is companies that aren't huge, but are big enough to actually warrant meaningful marketing via social networking sites.