Right, that's their whole business, as is Google's. They developed a platform that takes their valuable data and allows for targeted advertising, and they sell advertising on that platform. The advertiser never sees the actual profile page or even know that they showed an ad to a particular user. Only the platform and the algorithms know this.

"Creepy" levels of targeting is pretty subjective. I don't think its creepy because the other side is essentially oblivious to who they're advertising to. I'd rather see no ads at all, but if I had to put up with ads, I'd rather see ads that advertise topics that I'm interested in rather than something that's completely irrelevant to me.

Of course, that's just my opinion.