I mistakenly gave my number to a bot on Tinder, and now I get random texts on WhatsApp all the time, consisting of a highly photoshopped photo of a woman and some short intro.

I don't know if I have ever received an iMessage spam, and I have 6 addresses associated (5 emails, 1 phone number).

SMS I get spam almost daily.

I've gotten local political messages from volunteers, but those were sent from their cellphones (and may have resulted in them being banned from iMessage a few days later)

I've never gotten an automated spam via iMessage protocol.