I always thought it meant “just kidding”, but I suppose it’s actually “sticking out your tongue” – which, of course, I don’t do in real life after a joke. Not even a really bad one.
Am I the only one who thinks that? Do I need a smiley spellchecker now?
People don’t actually roll on the floor laughing, even after a good joke… do they?
And if they laugh their asses off… do they grow a new one? Or get it reattached? 
I’ve always thought of it as the lol-ling tongue. Just a funny face.
Oh, how I’ve wished that I really could laugh or work my ass off! But I digress.
I’ve always used to signify that I’m being goofy, as though I were making a silly face where my tongue was hanging out one side of my mouth. My use of it is definitely more akin to “just kidding” than sticking one’s tongue out.
Yeah, it’s a goofy “just kidding” or “I’m being silly” face.
Someone doesn’t know about the Thorn character?
Oh, ok, here:
So there :-Þ
Just like “LOL”, I interpret it as “I’m stupid.”
Harsh… I was never much for smileys, but I still regularly used “lol”/ “LOL” up until I quit instant messaging a year or so ago (though only when I actually laughed out loud, using other indicators for other degrees of humor-appreciation; to me and certain friends, the whole point was to give proper feedback). Interestingly, on these boards, I seem to be the opposite; I don’t think I’ve ever used “lol” here but I’m not above the occasional disambiguating smiley (as makes sense, considering the local linguistic norms and perhaps just the different culture of a messageboard vs. an IM conversation between friends).
Anyway, I agree with everyone so far: generally denotes “I’m just goofing around”.
In my own posts, I’ve always used it as shorthand for “Yeah, I know this is sort of lame. So what?”
I don’t mean to be. It’s not a conscious decision. It’s just my gut reaction. For the record, I’ve only seen “LOL” in emails.
I don’t know, maybe it’s just me, but I always interpret or as razzing someone or blowing a raspberry. For “just kidding,” I use a winky smilie, or 
Huh, I always interpreted it as meaning ‘I just did something stupid.’ Like letting your tongue hang out instead of sticking it out. I guess because looks kind of squinty and bleh.
An indication of sarcasm, irony, or a lame joke.
Until I got here (actually, until well after I got here), I thought meant you had your tongue sticking out because you were nauseous/exhausted/feeling blah; I couldn’t figure out why people were using it with jokes… Also, to me the the corresponding SDMB smiley ( ) just looks like it is laughing.
THORN character!!! It now has a name. I’ve been wondering for years what that was called!!!
>;~Þ
I take it to mean: “I’m teasing you in a very lighthearted/whimsical manner”
I take it as teasing, poking fun.
I take it as a neener neener, but I love you anyway, so I’m being cheeky.