No, but last.fm had [or might still have] a similar feature. It didn't tell the exact matching percentage though.

Never heard of it, so going to assume you're making it up for shits and giggles.

No. I'd try it if I had friends.

never heard of that feature, sounds cool. been meaning to make a Spotify playlist so it could maybe make me some good recommendations but have never gotten around to it.

I haven’t used it, and do have a Spotify subscription. How does it work?

No.