Since TechIMO is now a good sized, well-visited board, it's gonna attract those who want to sell stuff. Any where there is a crowd, you'll find hawkers.
So there will be those who only come here to sell. Not necessarily spammers, but those who join up just with the intention to sell those spare bits they have.
An Aussie forum I was in had so much of a problem with this, they made a rule: you had to be a member for 3 months before you could trade on the forum. That was to stop those hit-and-run spammers who diddled innocent buyers.
Of course, as TechIMO has the Troll Hunters to call on, that's not needed here, I don't think.
But the rules of good trade still apply: be careful!
Cheers
Mick