I wonder when this showed up in the idea creation. It all depends on a very actively audience engaged with the regular ads (in order to respond to comments via video response). Did they see the popularity and have an idea on how to use social tools to mid-campaign or was it in the works all along? Either way, genius.
I've used dropbox for remote teamwork. The experience worked magically, and the non-web savvy group interacted with it well. I even got enough bonus space for inviting new people to store our entire project.
One issue: because editing and saving is not live there were some issues, namely that we had to coordinate who was using the document when. We ended up with several conflicted copies and extra work.
I see this as an incredible leap in branding in the most unexpected places (forms) for those sites that want to go above and beyond in appearing personal, innovative and positive. As an A/B test (as has already been pointed out) it proves nothing but deserves further insight.
This is a great article and I agree with it. However, I think a second point can be made that odd numbers are generally better with most collaborative groups(be it one or three founders in this case).
Alternatively, strategies like this could segregate users on search. Football and Nascar on bing and an entire class of citizens have left Google. Makes me think of Myspace and Facebook.
I would wonder if there is a fear of hiring black men for extremely poor paying manual labour jobs for fear of the perception of slavery & racisim too.