Check out WikiAbuser for details on what kind of behavior gets you this title.
Basically, Dave is really reluctant to ban. He doesn't like doing it. It breaks down the whole structure of the wiki, it's not a GoodThing. But some people just have to be banned.
Dave generally bans first time offenders for two days. Special cases may end up being longer. However, if you try and evade the ban, by using a different Internet access point, then Dave gets pissed. That's at least a week of banning. If you keep doing it, weeks keep piling on. One person actually was aggressive enough to get a perma-ban, because he started mailing Dave cussing him out.
Don't do that. Never meddle in the affairs of wiki maintainers, for they are subtle and quick to anger.
If you do think you've been banned for the wrong reasons, you can 'politely email DaveFayram asking for a release of that ban. Don't cuss. Don't get pissed off. Just email and say, "Hey, my IP address is <blah> and I use the UserName <blah. It says I am banned, why? Can I get unbanned please?"
Some savvy people may think that they can evade bans by coming in from very large contiguous IP groups (CIDR addressing makes web administration harder in this regard), like AOL or Cox Cable. You are perfectly okay in thinking that, but you're wrong. Dave can and does ban people in these groups. He can make specific and semi-magic exceptions for people who are collateral damage in these cases. In the end, Dave reserves the right to ban people for any reason, this is just to make it clear that he has the final say in these things, and to not get into long debates about the morality or ethics of the ban later.
In general though, Bans will be a last resort, not a warning shot. Wiki isn't like message boards. We're not a pack of laughing hyenas like some web communities.