In fact, it might even be older than that, though not Victorian-old like some text speak. The first documented use was in a newsletter from a software company in May 1989, but a man named Wayne Pearson says he coined it in the early to mid '80s when his friend said something so funny that he couldn't help but LOL, and so it was typed.
It's hardly the only acronym to hit this milestone. The 1989 newsletter is a glossary to all the shorthand one needed to prepare themselves for the information superhighway. Acronyms like BRB and BTW are there, but the best are the ones that didn't stick: LTNT (long time no type), TTFN (ta ta for now), and LMTO (laughing my tush off). Maybe they'll make a comeback in another 25 years? (Slate)