[awinter-py]

I think you're mischaracterizing the promotions tab. When users interact with a web merchant, they're exchanging money for goods/services -- they're not signing up for spam. Hiding marketing email is a feature, not an evil plot.

It's not just G that differentiates between transactional email (a receipt) and bulk/marketing mail. Trans/bulk are so different that email companies consider these separate products (e.g. mailchimp vs mandrill).

Generalizing based on myself, I can guarantee that people really hate receiving crap. At least I can visually distinguish the G ads from my email and ignore them.

[TheGrumpyBrit]

I found the Promotions tab to be a really handy "middle ground" between spam and actual mail. It usually contains mail from companies I've done business with, who I might be interested in receiving offers from, but I don't want those offers mixed in with my day-to-day stuff. Having them separately allows me to read them on my own time, and also lets me see at a glance if anyone is sending me too much. They're also usually the kind of companies who will honour an unsubscribe request.