One of my favorite tools builtwith.com was out of commission today. It was showing a 503 error Service Unavailable.
The builtwith blog mentioned that they were working on the issue. It looks like they are back and running now. I feel for the team, I’ve been there. It’s not fun. Their twitter post explained it: https://twitter.com/builtwith.
Another cool thing about builtwith.com is that it is written in C#. http://blog.builtwith.com/2011/12/15/what-is-builtwith-built-with/