It's understandable to some degree though, several million people were using the tool, and the cost of keeping the servers up and running during heavy load (such as patch days) was no longer being balanced by the meagre income from the advertisements. Some of you may know, they've been working with the curse team for a good while already, mainly being helped with bandwidth.
But, as of this week there's no way back to the old WAU. Instead you'll now receive an error in your WAU client and log files that will inform you to go and visit this link and download the Curse Client. There's plenty of people who will, I'm sure. But personally I really can't be bothered with curse. Aside the fact that I've once again forgotten my username and password on that site.... The site layout is horrible beyond belief. I could list a number of things that could be improved, but I'd just be helping them in the end. The older layout from a year or 2 was better, get a clue guys, and kill the need to do "everything". Focus on WoW.
On top of that... The curse client needs you to log in. Didn't I just say I forgot my username and password? Of course I could recover them, easily enough, but why on earth do you persist in having people log in to update something as simplistic as addons? It wasn't needed before, it should certainly not be needed today.
Fear not, as there are alternatives. Or at least one so far that I could find. The program goes by the name of WoW Matrix and supports over 1500 individual addons, including most of the ones that the old WAU used to support. Isn't that great? It even supports Vista (ugh /spit), which is something the curse client doesn't.
I've managed to install it and update most of the addons I got running. A few things came to my attention.
Plenty of addon updates will be coming to your wow client the next few weeks surely. What will you be using to get them? Manually update 100+ addons? HAH! I think not.