Today, my account was "lucky" enough to get those...
The tabs are:
Primary, Social, and Promotions
Screenshot: 2013-07-12_1613 - callenb's library
The Promotions tab displays any broadcast emails that I get from marketers that would normally just show up in my inbox (i.e. the "Primary" tab now).
I would imagine this is going to completely kill open rates. Do you guys know anything about this that I don't seem to know?