In this particular case it was a post to throw the mods off the scent, since it was presented as conversation without a link. Only one of the posts I saw from this particular account had the link.
The link is like a Google ad. If someone clicks on it the spammer gets a fraction of a cent credit. Once their account builds up enough credits they get an e-transfer.
The best part is it's set up so they need to get many thousands of hits before receiving a payment so most of them probably never get anything.
Therefore most of them are just as you figure, working for free.
So you are right, they are actually doing it for the hope and dream of one day getting a ten dollar transfer.
That is why they use bots though, then the program will seek out, join and post on forums increasing volume.
Here is an audio clip of the thing from Idiocracy I was referring to. The premis being he was spamming people in person. I feel it is relevant and funny.
Well, it's hard to speak for other people's motives.
But I think the payoff is that if they can impersonate real people well enough, their spam links have a better chance of being taken seriously by someone who comes across them. Or maybe it's just that their odds of not getting the boot are higher.
Or maybe there is no payoff, and it's just the programmers having fun...
“Life is a shipwreck, but we must not forget to sing in the lifeboats.”
― Voltaire