In the "You've earned" messages "Enthusiast" has not been renamed to "woot!". Is this a bug?
In a Stack Overflow blog entry, "Enthusiast and Fanatic Badges", the renaming was announced: "For the period of sponsorship, we’ve renamed this the woot! badge. (It’ll revert to Enthusiast once that period is over.)"
Here is a similiar question - but I report it as a bug.