Social media is by no means a silver bullet, but that's not to say that it doesn't have it's uses for brands. Raising awareness, however, is something that social media can be particularly useful for.
However, the main way I've seen people do this so far is with viral content. Producing something that can go viral is very difficult for some brands - their culture does not support the risky, balls out attitude that does well online.
(If you have examples of viral content that does not fit this pattern then please let me know)
Other short form work also tends to go viral, YouTube is often credited with rejuvenating SNL, despite NBCs insistence on taking down every clip
People are brands too. I almost only watch talk show interviews in clip form.