When a new player joins the game, they're in the /trade channel by default.

What this means:

Newbie joins game, plays for 5 minutes.
Newbie has a question about the game.
Newbie types the question and hits "enter".
50-bajillion WTS/WTB messages appear. Newbie is lost in a sea of text, unable to read it all.
A helpful player types an answer.
Another 50-bajillion WTS/WTB messages appear, pushing the question and answer clear off the chat box.

Newbies never get to see the help they need. This happens far too often. There's no need for them to be part of /trade so early in the game, half of them don't even know what crafting is.