I have been working within a B2B company for almost a year now and been involved mainly in generating leads through the company's websites. The nice thing about working within a B2B framework is to see how to apply the innovative and smart techniques that are adapted across the web (which is consumer centric) into a business model where most of the target audience is not looking for the business online......... 

B2B Digital Marketing

The world of business is evolving online and new models are maturing as we speak as more businesses take their hats off and let go of their historical views to adapt to what is going online. 
I need not dwell into the how and why of this move because it is more of a way of life.. if you want to exist you need to be online....  What I present here is my personal experience about what can actually be applied for B2B in comparison to what is widely available to the B2C consumer oriented retail business model.

We all know display ads are key elements in brand building and brand awareness, and that social is the way to go to get your consumers involved in your business. But what if you are a business and your customers are those high end professionals who would not be intimidated by a flashy display ads or welcome an invitation on Facebook , since they believe facebook is for their kids and families...?
Well , what worked for my company as a key software developer in a very high end industry was a mixture of PR, PPC ads, and social presence on Linked In, Twitter, and Digg where most press releases, blog pieces and articles where posted.
Furthermore, the communication message and all online activities were basically driving people to the website to read content and hopefully be curious enough to register on the corporate website and request more information. To top that was simple, down to earth house keeping through standards search engine optimization (SEO) work that pushed the company's website up on the search engine ranking for the key phrases that were selected.

So to answer the question, social marketing for B2B should be applicable with the right mixture that guarantees the right message is delivered to those who might be willing to receive it; because without this reassurance businesses would be drowning into this ocean of techniques and methodologies not knowing what went wrong....