This is pretty much my position too, especially if they post a message in a forum and never reply to inquiries there. That goes for individuals as well as commercial entities. To me, forums are for conversations. (Sorry, I have some pretty archaic ideas about how forums are supposed to work.)
Originally Posted by kev74
If you want to designate a place where classified ads can be posted with the understanding that further questions will be handled elsewhere, that's fine. As long as readers know they have to use other means to get more information.
How you control posting privileges to an advertising space is up to you. Whether you charge for it, grant it based on participation, or make it free, you're the one who has to manage it.
"A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects." - Robert A. Heinlein, "Time Enough for Love."