The toll-free phone number for technical support at Apple. It's gone downhill since circa 1996 when they canceled unlimited telephone support, but that's another story.

Anyway, this particular number has fallen into disuse partly because of the not-so-free support after 1 year, and partly because people would dial the O as a zero. Coincidentally, the number with a zero happens to be a sex chat hotline in the US. The same thing happened with one of the US Government's flood hotlines once.

Yes, I've accidentally done that

Phone: Hi, Baby! You've reached the sexiest chat line in America!
Me: ?

Who says Mac users don't have a better time than PC users?