According to Mr. Random Ravings WotLK has made a slight change to macros.
Macros and key bindings are now saved server-side so there is no longer a need to reconfigure them when logging in using another computer.
This might not mean much to most people, but take it from someone that logs into his account on up to 5 different PCs/laptops.
This is GOLD with an extra double-sized italicized bold capital G.
I have tried many times and given up, creating the very same macros, in the same order with the same icons and names and everything on another PC and they still don't show up in the same slots when you log onto a different PC and you then have to replace them on your bars all over again.