> What I would love to know is who is selling my info.

Car dealerships. Heck, even the DMV. Sign up for Credit Karma? Enjoy credit card offers arriving to your house. It seems everyone is "in" on selling/sharing our data. If you ever read the terms of services, you'll usually see a "third party partners", or something like that, which mentions how they "share" your data.

Opt out should be the default, but it isn't.