How about not completely restructuring the racing forum so people had to go to regional forums which in turn killed the racing forum. Took one of the fastest moving forum spots and made it one of the slowest.
Also when in the for sale forum when someone files a negitive feed back on you because you gave them a negitive feed back. That makes it much harder too want to come here too sell or trade.
Uploading pictures could be easier and the site could also have the option to lock it in the desktop version over the mobile.