It’s amazing how spammers will use every single vector to send stuff to us. I suppose if the cost of sending it is so low they have nothing to lose even when the take up is very low.
A new vector (probably) hasn't built hardness yet against spam, like for example email with apps like Gmail filtering out most spam and SPF etc.
If you start a forum, you expect spam, and there will be tools in the forum software to deal with it. But something new that isn't a traditional place to spam may be caught off guard.
"Hi buy this pill quick and cheap from http://here*, you requested a password reset"
Hhhhhhrrrrgh