I've engaged in debates in Yahoo chat rooms for years and years, and I'd like to share some of my insights regarding the theist's side of the debate (from my POV, being atheist) -
There's the stereotypical troll. Makes a controversial statement, then moves on to another controversial statement, is spouting a monologue and does not engage in debate. Easy to spot. Does it to get attention or to rile people for fun or to validate their faith: "Oh, look, I stepped into the Lion's Den and prayed for them. Yay."
There's the 'ditto' troll, or the plagiarist. They will lift other people's work - sometimes word-for-word, sometimes with their own re-wording. Usually fairly easy to spot, may or may not ignore the fact that whatever they're plagiarising has been debunked.
There's the engaging troll. Makes controversial statement, actually tries to defend it. Ignores inconvenient facts/realities/evidence and never presents a compelling counter-argument. Most of these last about three levels of facts deep, or three levels of reasoning - about as far as any of them can think, because they never commit their thought processes to paper/writing. i.e., they will attempt to explain their own crackpot theory about why Marmota Monax chews cud and is therefore not kashrut, so Christians observing Groundhog Day are going to aitch-e-double-hockey-sticks. This ignores Jesus liberating everyone from the Old Testament laws. This was an actual crackpot argument.
Then, there's the thinking person with faith. These people make for great conversationalists, have thought about what they're doing, understand that atheists genuinely lack faith, lack belief in deities.
In many, many years, I've only had one memorable, /actual/ debate with someone 'of faith', and it was with a person of this vein. He is a philosophy major, and in about thirty minutes we boiled it all down to "Well, I have faith in this all-pervading intelligence, I just do - and I have no facts to back it up, only my feelings and experiences." No ad hominem, no ignoring points, no cherry-picking data, no thoughtless regurgitation of someone's debunked crap.
95% of the time, the particular 'debate' room acted as a social setting - for people to gather, offer community, bait the 'other side', scoff at 'the other side', discuss various things, talk about the political weather, and present or tear down a metric tonne of bullshit. It was practically a CSICOP coffehaus.
5% of the time, it was actual debate - with people who actually understood what it meant to debate, how to do it, and followed the procedural rules.
If you're wondering where to get more info on this, google "Atheists vs. Christians Yahoo" or some such. I'll see if I can't find some resources that we might have links to.