By now a metric buttload of folks have downloaded Firefox 3 and are cogitating about what they think. We think it's flawed but nifty. And, of course ... the easter egg, it haz it:
Go to your address box and key in about:robots to find out some neato facts about robots:
Anyone sufficiently evolved to know about the about: in the address box also knows that about: is one way to tinker under the hood.
About: can do a hell of a lot though. Surf this post to find about whatall. If you want to be a Firefox power user, you'll want to do this.
The button reads Try Again. If you click it, it changes to Please Don't Press This Button Again. If you do, it disappears.
Also, they have a plan. Whether this is a time to worry is not at all clear.