I saw some websites where they had their ToS and/or set of rules a little more developed.

Not just "don't troll, don't flame, don't spam". They explained what they considered trolling, what kind of insults would make you earn the "troll" or "flamer" categories.

I noticed that, after upgrading my ToS/Forum rules I lost some members, but the overall useful content on my forums has increased substantially.

At Tenths we run a fairly tight set of rules in the FAQ and while it probably means we get less posts per day than some similar forums we also have a better reputation for quality of content.

I guess it all depends where you're aiming your forum.

We also have rules about not advertising other forums, not advertising your own website, and not having images in signatures, all of which seems to cut down on the "noise to post" ratio.

I don't like forums with too many rules, so I try to keep the rules to a list of things that any normal person would find obvious (no trolling for example). This combined with some active moderation keeps the noise down.

Chroder: How many posts are you (and your moderators) dealing with in a day?

TNT is still new, not many there. On WMT we get about ~450 a day and our rules are here (http://www.webmaster-talk.com/news-and-announcements/announcement-important-webmaster-talk-forum-rules.html).

Spam is a really big problem on WMT, so we have special rules for some forums. For example, I wrote a plugin for the Site Reviews forum that forces users to review other sites before they are allowed to post a review request of their own.

I dont have a ToS posted, but i do have a few forum rules posted in certain forums..

Most of my forums are private (must be approved to post) forums, so our TOS are much less developed and we rarely have problems with people causing problems.

I just make em miserable :).

in my forum, only my moderators and admins know the rules, so if a member broke it, they just notice him. with this thing i earn more members