A somewhat more serious, if equally narcissistic, reply.
The ways I communicate on here - humor, vocabulary, favorite talking points and buttons that can be pushed - that's all true to real life. I make lame puns, I use unnecessarily ornate language, I waffle over philosophical thoughts, and I can be passive-aggressive/self-righteous when dealing with people who antagonize kids, well-meaning folks, or innocent bystanders.
There are differences I've noticed, though. Online, I say more. That's because it's all written, I think. What would cost me a sentence and a tone of voice in real life might cost me a paragraph or two here. The trouble is that I'll end up writing more but conveying less, or conveying it poorly. There are times here when I've written something I intended to be clear, reasonable, and pointed, and it ended up sounding more long-winded and combative.
That's had the effect of getting people upset with me and leading to boring, annoying, mistaken problems we'd never have offline. A few years ago, I cared enough to try and avoid it, but lately I've given up on trying to polish and protect other people's opinions of me - it's too easy for somebody to misconstrue their own points or the points of others, and trying to run around keeping it all accurate and getting the communication clear takes way too much energy and is often unsatisfying anyway. Now I just do the best I can and let other people keep up their end.
That's the major thing, anyway. Online, I'm apt to say more than is necessary, just because I'm writing and have the ease and time to fall into overspeaking. In real life, more often than not I'm listening instead of speaking. I'm generally well known in my social circles for speaking only that which is appropriate, and only at appropriate moments. Unfortunately, it's far more difficult to express reflective wisdom online.