This may not be Web 2.0 but it is definitely proof that some people have too much time on their hands…
http://$urlcalc(help).x42.com/
If you need to know what 212×17 is then go to http://$mul(212,17).x42.com/
Brushing up on your RFCs? http://$rfc(1725).x42.com/
Google must have used this site as inspiration for their search calculator: http://www.google.com/search?q=212×17
