[dunnevens]

FB allows commenting on ads. This does not go well for certain types of advertisers. Political and religious ads especially. Even the bland corporate advertisers have to spend some time cleaning up the inevitable mess.

What's especially puzzling is that FB allows image uploads as an ad response unless the advertiser was smart enough to disable it.

[r00fus]

Well, you could call this "engagement", at least people are clicking and investigating.

Also it appears Twitter does it as well - so many promoted tweets are just roasted in the replies.