Registration

From a purely practical perspective, the only way to force people to use real names - with associated a valid e-mail address - is to require registration. We've talked about this as recently as last October, and even ran a poll on the subject once upon a time. The results were that about 55% did not want to require registration to post on the board. (Actually, we could get really snotty and require registration to read the board, but nevermind).
Most people are not completely anonymous since every time anyone posts, the IP address of their computer is recorded along with the post. In many cases, his can allow us to figure out who an anonymous poster is by comparing a post with a name to an anonymous post. There are problems, for example, people with dialup will usually have a different IP address every time they connect, and in other cases, there will simply be large numbers of people using the same ISP - but even then, we can develop a list of "suspects". We can show these IP addresses, although using them to determine exactly who someone is is not an exact science.
The anonymous posting problem is one that we have historically accepted. As has been mentioned, there are occasionally good reasons for someone to post anonymously, and, anonymous posts can generally be easily ignored. However if the general feeling now is that people want to move to a registration system, we can do that. It'll be a little ugly starting everything up, but it's doable.
Don