“The tar program, starting in Mac OS X 10.4, recognizes and handles resource forks and attributes.”
Examining the unsaid, it turns out that Apple’s Unixy command-line tools like tar, gzip and all of their friends don’t work properly on 10.3 and earlier. “Don’t work” here means “don’t include resource forks”, which means significant breakage.
So if you, and by “you” I mean “me”, should suddenly find out that all these Mac apps you’ve been deploying across your highly heterogeneous enterprise are showing up on people’s desktops as anonymous Unix applications, rather than Mac apps with Mac icons, and just generally not working at all for anyone even though the whole thing worked fine in the lab, dammit, that’s what’s going on.
Now you know!