To debate or not to debate. That is the question.
What I will share is just my humble opinion. It's based on trial and error [and a lot of error], but each person may have a different experience.
Personally, I don't recommend internet conversations. The reason being is manifold and I will share some of those reasons here along with an alternative end goal for online debating.
Reason 1: Emotions Run High
The internet can be deceptively intimate as well as offer a sense of safety from immediate consequences. As a result, people can be more nasty and terse online than they normally would be in person. This isn't only with your internet infidel, but with many Christians as well. Look over any blog on apologetics and you will see comments from Christians calling people morons or other ad homenim language.
There is nothing truly intimate about the internet and a face to face conversation over a cup of coffee is always a better approach.
Reason 2: Multiple debaters
Usually, you can have a conversation with one person and it always ends up involving 70 of their 'defenders'. It's hard enough making a reasoned argument with one person, let alone the entire Richard Dawkins Facebook fan club. Often your point will get lost and a multitude of unrelated objections get slung into the thread exhausting you to the point of frustration.
Reason 3: Your grouped in with bad debaters
Let's face it, there are a lot of well meaning, but ill-informed Christians out there who make very bad arguments and use old cliche's attempting to convert the internet atheist at hand. Not only will your arguments tend to get lost, but you will be grouped in with their statements and end up having to defend or detract those statements and never getting your argument off the ground.
A Stone in Their Shoe
Now some people love this sort of thing and are very good at it. But, I would offer an alternative goal. I have found sometimes that simply asking a question to dig out why someone holds their view does more than writing a 10 page argument on the resurrection in a single comment post. It exposes some of the faulty thinking in the view for all to see. Then, you can leave the conversation as it is without moving any further. I have found this to be helpful at least in giving the other person a better sense of kindness on the part of Christians than they usually experience on the internet.
So, if you are going to debate on the internet, I recommend following some simple rules:
This can change the experience not only for you but for the person you are chatting with.