Admittedly, I'm the kind of guy that likes to Argue on the Internet. Yes, this activity is of debatable (heh) value, but I acknowledge it as a guiltly pleasure. I hold no illusions of being able to truly sway a person of deeply held convictions and, there is a certain element of self-satisfaction.
However, I can say with honesty that my interactions, as argumentative as they may be, have helped to refine and change my own convictions. For instance, I used to labor under the notion of agnosticism existing as a "third option" between theism and atheism. I now understand that (and why) this is false.
This activity does come with a down side. The internet is full of crazies and isn't exactly a medium that lends itself toward civil, formal debate. That is why I have been happy to have come across http://www.debate.org/. It's a website dedicated to - or at least trying to - formalize the debating process. Now, it doesn't necessarily adhere to any strict rules, at least none that are enforced, but it is certainly structured. Debates are organized into rounds, there are Pros and Cons and while there are certainly people who vote just to support their predetermined position regardless of the effectiveness of the arguments presented, the community, as a whole, seems to judge debates fairly, based both on style, substance, and references. I encourage anyone that enjoys debating to check it out.