Looks like ASP.NET from the .aspx file extensions

See Netcraft: http://toolbar.netcraft.com/site_report?url=http://allrecipe...

Presumably this is some of the hardware they are using: http://www.f5.com/products/big-ip/

Content Delivery Network for media (images, css, js): http://toolbar.netcraft.com/site_report?url=http://images.me... http://www.limelightnetworks.com/

You are correct, it is quite fast.