Great article on single-purpose web sites - from Lifehacker.com

Lifehacker.com has a great article on web sites that do what they say:  Need to perform a speed test? Check the security level of your password?  Find your IP address?  This article has a lot of great resources.

http://lifehacker.com/5860925/our-favorite-single+purpose-web-sites-that-do-exactly-what-they-say-they-do