IRL, I’m Batman, although for some reason I’m never quite prepared.
D’yah know why that is, astro? I reckon it’s because you keep forgetting to wear your underwear on the outside of your lycra tights! 
I’m pretty different in real life too, in fact - I’m pretty much just like what HerMajestyLorna described herself as.
But the there’ll always be one thing about my personality that I’ll never display on the boards: I’m extremely impatient and short-tempered and I swear a lot without even knowing it. Well, that’s two things and I can’t be bothered to backspace all the way. So, uh… deal with it.
IRL, I’m incredibly boring because I sit at a computer for too many hours reading about the lives and loves of people on the SDMB.
And when I actually get motivated to LEAVE the 'puter, I bore the pants off my kids and workmates about the lives and loves of people on the SDMB.
So, I guess my personas are the same.
I’m much more talkative in real life. I think it’s because I have time to think before I express myself.
Also, I often have something to say on the SDMB, but I can’t make the words fit what I want to say. It’s weird, because I have no problem spouting out long essays etc for uni.
I think that a lot of people have different presentations of themselves. Look at how someone you know acts at work, as opposed to how they act when they are with family.
I’m much more reserved IRL, perhaps because I worry that the people I’m talking to don’t care or are bored by what I’m saying.
I guess I’ve seen people trapped into converstions that they don’t want too often, I’m a bit paranoid about doing that to somebody. It translates into shyness and not talking much or at all to people that I don’t know well. I hate parties with a passion, even office get-togethers where I know all the people. If it’s not an office party that I can’t get out of, or a gathering of my family and friends, I don’t go.
With family and friends, I am very much more outgoing, even wacky. I’ll butt in and tease, joke and laugh. I don’t have very many friends, but I am very close to those that I do have.
Online, I am a mix of both. About half the time, I will start to reply, decide that I don’t have anything to add to the conversation, and not reply.
I appreciate your suggestion. Thanks for taking the time to offer it. However, I’m 42 years old and I’ve lived this way my whole life (except for the years when I drank every day in order to interact normally with people) and I’ve tried a lot of different remedies, including counseling and various medications, all to no avail. Some were voluntary, others imposed by well-meaning folks who thought they could fix me. After many years of fear, self-loathing and abject isolation, I’ve come to accept that this is who I am.
As for art therapy, the notion makes me smile. I am an artist–have been for most of my life–and while I’ve found that it can occasionally have therapeutic side effects, for me it’s more of a necessity than a luxury. I don’t dictate what I’ll do or when. I know that it smacks of pretentiousness to speak of a muse, but there’s no better description for what motivates and sustains me. If dedicating oneself and one’s life to obeying a relentless compulsion can be considered therapy, then I expect I’m about as healthy as I’m going to get.
Depends on my mood, I’m a chameleon. I can be an ear or I can be a mouth. I can be sweet, caring, funny, compassionate or a total bitchy wench from the lowest pit of hell. Same here as in RL. My SO doesn’t post here, though.
I seem to have so many facets to myself that saying if I act differently here than I do in RL is not applicable at all. It depends on my mind frame, mood, state of being for that moment when I post a comment or react to something in RL. I try to maintain a pleasantness for the most part so as not to annoy the rest of mankind (except for my mother, she’s insane so I get super duper annoyed with anything she says or does and I’m not so kind).
Usually, I do care. I do have a nurturing side to me that comes through no matter how mad I am. I try to keep things on the lighter side, too.
You’re welcome. As a (perhaps) budding psychologist, I feel it is my duty.
Sorry to hear that you haven’t found a successful form of treatment–although I’m glad to hear that you don’t let it bring you down.
I’ve been thinking about something lately: the way artists talk about art seems to bear some similarities to the way addicts talk about drugs. Although, since art seems to bring such joy and meaning to those who partake in it (without the nasty side effects, hangovers and withdrawals), this is not at all a bad thing. Just something interesting to think about.
Not sure if you’ve heard of art therapy. To sum it up as well as I can without having studied it all that much, it’s a form of counseling which involves the patient creating art in various forms to express themselves and get their feelings out. The idea is that people who have trouble getting their feelings out any other way can get them out through art (going back to my little analogy, this is quite similar to LSD/MDMA psychotherapy, which good old Uncle Sam has squelched for political reasons). You seem to do this quite well without having to pay any psychologists; more power to you. If you haven’t looked into it, though, it might be interesting to take a look at. At the very least, you’ll have a smile or two reading about it, right? 
This is interesting to me because my OL and IRL personalities used to be very different. I first got online when I was about 13 and, through a roleplaying forum, I discovered the idea of “personas.” Through roleplaying online, I really learned a lot about the strength of personality…IRL I was much more withdrawn, moody, awkward. I found that even in non-roleplaying online conversations, I was really coming out of my shell, being engaging, sometimes funny, even flirty. As sappy as it sounds, being online taught me that even though I’d never be a bombshell, I could still wow folks with my personality. I think that now my personality OL and IRL are much more similar.
My online and real life personalities are identical - what you see is what you get. 
I think I come off as more of a stodgy old crank online. Mostly this is because I don’t have a lot of time to post, so I tend to post only when something gets me worked up, and that means nobody ever sees the witty, sparkling side of my personality here.
The on-line me is much closer to the real me, the one unencumbered by shyness and stuttering, zero self-esteem. The me that walks down the street is the biggest falsehood.