I think the change is a good idea.
I believe that the idea is to encourage members to contribute something to the forum by way of starting or contributing to a thread, rather than just using the forum as a shop.
That said, I buy and sell a lot of stuff on here, but I have also started one or two decent threads.
After all, the service you get on here is free, and I appreciate that.
Unfortunately, if I buy a gun that leaks, I moan a lot.