When there are no mods it's all on the honor system, and in my experience, it doesn't work. If there are no consequences, people will do whatever they want, they'll push it as far as they can, say really vile things, and sometimes even "hack" into your personal life through their computer wizardry. I've had a pretty bad experience myself somewhere else, and my choice was to just leave that forum.
It really comes down to what you're willing to tolerate. I miss a lot of the people I used to talk to, but in my case I decided I wouldn't participate in a forum that had no standards. Honestly, if a forum doesn't realize the need for mods, I would question the value of that place, or at least of the administrator/owner. Often times they are just normal busy people with jobs though and don't have the time to read all the threads and keep people honest.
So I guess in my case it came down to defining to myself, what my personal boundaries are, and being willing to have those standards, even if it meant having to lose touch with some people I was close to.
Good luck.
