Regardless of its purpose, Sony has announced that the next version of the PlayStation firmware, v3.21, will remove the Other OS functionality from the older PS3 units, as well. Users won't be able to access any sort of alternate OS partition following the update, and Sony has recommended that any users looking to upgrade should back-up their data from that alternate install before proceeding.
The reason cited is "security concerns." This is probably related to the hack released back in January by "George Hotz," who also released a pretty snappy iPhone jailbreak tool last year. The hack used code running in an Other OS install to eventually grant users full low-level access to the PS3's guts.
So, if you value your Linux install, you'd be better off not upgrading when v3.21 hits on April 1. Of course, if you don't upgrade, you'll lose all of your online access and, eventually, newer PS3 games that require a higher-level firmware install won't run, either. Not to tell you how to live your lives, but a PS3 that doesn't play current PS3 games doesn't sound like much fun at all.
Did any of you ever install another OS on your PS3? What did you use it for? I always thought about doing it, but then I also bought the PS2 Linux kit and never actually installed it.