I don't know any of the specifics for the squeak.org site (Chris Cunnington may be able to give you a better answer), but I know that the new site is done with Altitude, which is MIT licensed and freely available:
http://news.squeak.org/2012/07/23/altitude-in-the-cloud/
http://lists.squeakfoundation.org/pipermail/squeak-dev/2012-July/164881.html
Dave
First, thank you for the new site. It looks great.
Is the source code for squeak.org available for people to putter with and try out new ideas?
thx.
tty