misfire200: Yeah, it is not good for the community with a couple of bad apples, and GOG's particular format does not help things. But even a simple "stickied" topic on the matter would not hurt. I am actually surprised GOG by now does not have a more robust search engine or ability to view profiles/prior posts easier. Heck,
this is probably the only forum I regularly check that feels so out of date. Just requires better policing....also if you get an offer from someone you cannot search for or find...post it in the classifieds and see if anyone else has gotten offers. I am pretty sure this trashbin fellow sent offers too multiple people probably offering whatever that person was asking and only involving steam.
On the first point, user profiles could help, because if someone didn't trade properly, people could add comments about them being untrustworthy. But GOG is concerned about selling games to us, and trades are 3rd party, so i doubt they need to do anything about it. Although Steam does allow trading of their own codes.
As for Policing, i've asked for "community mods" before to help clean up spam and look after the forumn in general. But if GOG cannot stop people like wakalo, then policing the forums wouldn't prevent the problem any more than we can right now.