I'm wondering how on earth these people were tracked. Let's say you get their IP address .. what then? You'd have to use a supoena to gain access to that user's personal information via their ISP. Any ideas?
I suppose you wait for people to use their real first name or real last name, and you keep track of all the personal information they post.
Eventually you'll be able to narrow them down to neighborhood, name, etc.
You can also track IP addresses to their general neighborhood, and if you know the first name of a person, you could check a phone book and see what you find.
Cross referencing.
Well, your browser can give away a lot of information about your system (and possibly you) that can help somebody find even more information about you.
Just going to a website and clicking on one of it's hotlinks can provide a whole number of possibilities for the bad guys via things like cross-site scripting, etc.
Google has gobs of information about people and sites, etc., and on and on. =)
If these Christians had spent much time online and posted at other websites, there's a really good chance that some foundational, personal information would be out there and available for free. Using basic information like that, for another $20.00, or so, you can apply to a number of services, online, that hold all kinds of information about people in the United States.