The viral buzzfeed website trend is pretty ridiculous lately, but i can definitely see why. If you're willing to put in the work to make a bunch of viral content, it's pretty easy from there.
A lot of the sites cram their pages with similar ad companies, yet don't try to make any custom merch, or even attempt affiliate marketing. What strategy would you test if you had 5 million monthly uniques?
I would look into building my own RTB platform a la POF.
As profitable as branding may be, the capital requirements are a little high for my taste.