I've never mentioned it, but a couple of people asked, and it seems to be mildly popular, or at least amusing: I'm trying out the Japanese translator link at the top of the page. It's a handmade URL that runs the greg.org front page through Excite Japan's site translator. The output's fairly accurate. Japanese will happily adopt a foreign word rather than use an awkward translation; Excite leaves some things as is, avoiding some Babelfish-style gaffes.
Of course, making translation available and building up a Japanese audience are two separate things. [Thanks to Jason for the heddo appu.]
