This seems very inefficient... requiring a forum post to sell something.  Why can't I just advertise on the server?

I was getting to that.

The Marketplace Forums are for selling very large or rare items, and by making a post here to buy, sell, or trade, you can not only do it in a moderated setting but also use your post as a sales log to keep track of who gets what.

You can still advertise items for sale on the server!  This is simply a dedicated section of the Forums that provides logging and a broad reach of item sales, to players both online and offline (rather than only online players in the server).

If you feel any shadiness (uncertainty, dubio...