Also known as BannedUser.
Banning users is a tricky thing. At first, it seems simple: Somebody disturbs the community? Just ban him. He’s not hurt, and you’re not hurt. You’re just denying him the service he was abusing in the first place.
When the “service” we’re talking about is a PublicSpace? such as a bar or a coffee shop, you will need a LegalSolution. You can’t just ban people because you usually have to provide non-discriminatory access. Therefore you must be able to prove in court why discrimination is necessary. This usually involves the use of your PropertyRights?: The owner of the premise bans a visitor and sends an official note via registered mail. When the troublemaker shows up the next time, you can call the police and have the person arrested because he/she is violating your property rights. And you have your registered mail to prove in court that the troublemaker knew about it.
On the net, the current opinion seems to be that this is not a PublicSpace?, and therefore you may discriminate at will. On the web, you have more power to do this, too, since you have access to the IP address (and via reverse lookup, to the domain name) of your visitor. Furthermore, if you system uses usernames, these are also accessible. Banning can therefore happen on all these layers: Ban IP numbers or ranges, ban host names, or usernames, maybe use pattern matching.
For banning options on this wiki, see Oddmuse:Banning.
Banning on the net also has some difficulties associated with it:
When banning spammers: Whitelists, blacklists, keywords – we have a wealth of information on fighting email spam. How to apply this to forums and wikis, however, is still unclear.
Banning innocent users is not a total loss, since these people share some resource with the banned users, usually an Internet Service Provider (ISP). These people can therefore act and get the banned users off their service using other means.
On the downside, you’re counting on them to act in order to participate in your community – a big expectation to make! Communities that depend on casual, MicroCommitment? participation, like wikis, may be losing valuable contributors who don’t want to, or don’t know how to, get a block cleared by working with the community admin, their ISP, or whomever.
Therefore, banning works if you’re getting lots of Chinese industry or Russian porn spam and your users are mostly non-Chinese and non-Russian, and you’re happy not ever having Chinese or Russian contributors.
We’ll see what comes up in round 2 of spammers vs. wiki.
Interesting approach. You have to spend the same amount of time on these issues, I guess, but at least you’re not blocking innocent users. I like it! piranha pointed me to the MT Blacklist plugin which publishes its list online.  If we’re worried about censure, we can always allow posting of such links and use the blacklist to just not link to the targets. This way they are denied increased pagerank.
Alex: I re-integrated the YHBT downside back into the rest of the list. I didn’t just mean trolls; any time a community resorts to a TechnologySolution rather than a CommunitySolution they lose some community strength.
I also changed the banning-is-ok block to show some ups and downs with that. It’s not 100% OK.
evan’s additions are why i am generally opposed to IP address banning, and much more in favour of careful link banning. so many people on the net now simply don’t know anything technical, and wouldn’t have any idea why they are denied editing a wiki, and what to do about it. it’s not … not wiki to make entry hard for them. and even though most of one’s users might be non-chinese and non-russian, what about that occasional english speaker, or expat who might want to contribute?
Link ban has been implemented for Oddmuse, so we can start using it once the spam bots discover where we are hiding.