Your mistake was a common one that we all make at least once: you jumped into a new playground without reading the rules, and accidentally broke a big one in the process. By your own admission, you did this a couple of times, and received the same harsh response each time. That should tell you something--not that the users of forums A & B are big meanie poopoo heads, but that members of forums frequently spammed by sellers are more likely to take overt advertising attempts badly. (You would too, if your conversations were always interrupted by someone pushing products.)