The sending
to strangers thing seems to be mostly men, and is quite an... odd... thing to do. I don't really know what it's about psychologically. Some sort of twisted form of peacocking, I guess? One of the main things seems to be, though, that for some reason a lot of guys now just think it's "expected" and that it's weird NOT to send one on dating sites etc
.
Overall, though, it's definitely not just a male phenomenon and when I was a young singleton (teens / early 20's)... I saw a TONNE of unsolicited boobies / underwear shots and quite a few vaginas too. Not from COMPLETE strangers, but plenty from "forum randoms" who I wouldn't say I talked to much, and certainly plenty who I only talked to "in passing" on the forums themselves.
None on TiBB though, I must have lost my touch in my old age / marital status
.