It means 'every situation is different' and it is the cop-out, fail-safe, fall back of the JET program. Want to know what grade level you'll be teaching, or how many schools you'll teach at, or the size of your house and or apartment? ESID. Want to know if you'll be place in the middle of nowhere or if any of your JTEs will actually be able to speak English? ESID. Want to know if you'll have bugs in your apartment or even running hot water? ESID.

Yes, it is the answer to everything up until the point you can actually contact your pred. And it is OMG annoying! However, it's the truth, so I can't complain too much. It's one of those things you just have to accept (along with all the waiting) if you want to be a JET.