On Submitterator, Musicman pointed me towards this great presentation on LOLspeak as a form of language play, and why people engage in that play. According to Lauren Gawne, who gave this speech last week at the Australian Linguistics Society conference, the choice to use LOLspeak has a lot to do with establishing identity—the playful identity of "cat", and the serious identity of "knowledgeable Internet user".
Includes an explanation of why LOLspeak is language play and not some language mashup "kitty pidgin".
You can read more about this on Lauren Gawne's blog Superlinguo.
The video, by the way, is 20 minutes long. It's also got a little bit of weird, warbly feedback in the audio, but that doesn't get in the way of hearing what Gawne is saying.
Maggie Koerth-Baker is the science editor at BoingBoing.net. She writes a monthly column for The New York Times Magazine and is the author of Before the Lights Go Out, a book about electricity, infrastructure, and the future of energy. You can find Maggie on Twitter and Facebook.