Two things that I think are very important and would be a valuable addition to TSS forums:
1) limited HTML usage -- possibly formatting only. Things like <i><b><u><li><ul>... etc, etc, etc. Maybe link tags, as well... for convenience when people link for referring pages. Maybe not put in links if you don't have moderators who keep track of the forums very frequently.
2) When replying to a message, a 'quote' button which will put the text of the message being replied to in the <TEXTAREA>. This goes hand in hand with the formatting. It is very important to show the _context_ of the reply... in order to be understood. Not being able to format quoted text (in italics, for example) makes this much more legible -- than simply putting punctuation marks around quoted text.