I just noticed on Microsoft's site that they are using a novel idea I haven't seen before in mass marketing - sticking twitter / feed comments from real users tagged with today's date onto the homepage, then linking into a full social queue.
EG - Check their landing page http://www.microsoft.com/en/us/default.aspx
I have managed hundreds of A/B and multivariate tests and i have a feeling that this strategy would be a BIG winner - relevant, recent, 3rd party, and pulling in a buzz brand.
Any other good examples of this?