I spend a LOT of time on Pinterest. That said, I am also pretty fucking oblivious. I cull who I follow pretty damn closely, and just started to notice some dude named "Martin" advertising a skincare line. I know for damn sure I never actively followed this person.
I am realistic, I KNOW these social media sites need to start with the ad revenue. I just wish they'd at least be somewhat transparent.
I went on a coffee date with this guy who runs a pretty popular humor site, and he told me he'd been contacted by Pinterest awhile back, so I know it's something that's been brewing for some time.