Yes, it is apparent to me that PPRuNe is "totally discriminating", to quote gcolyer. That is as it should be, and I support it. Though I am not conversant with the origin of PPRuNe, it is obviously private, and therefore entitled to discriminate however it [they] want within the bounds of society's acceptance. Complaining about it seems pointless to me.
It's like going into a private store, and complaining to the manager that they don't sell airplanes. They are not required to sell airplanes, they can sell or not sell whatever they like. You should expect a polite reaction back "well, we thought about it and chose not to sell airplanes". That response has been offered here. No further explanation is required, though that courtesy has also been offered here.
PPRuNe serves a different purpose, and to dilute it's resources to support commercial activity would be a poor idea. If it helps members to link aircraft shares for sale to members looking for them, I think that is help that is worthy of stepping into the grey zone. All grey zones need a far edge, and outright aircraft sale should be kept on the other side of that edge in my opinion.
BRL stick by your principles here. It would appear to me that whole aircraft ad posters have the potential for volatility, which just does not suit the helping and intellectual objectives of PPRuNe.
Perhaps the other member should start a thread "where's the best place to advertise my plane for sale?". I'll promise to keep my comments to myself, and refrain from posting "Not here" as a reply!
Pilot DAR