On the blogs.technet.com article on microsoft.com's infrastructure:
The article reads like a blatant ad for it's own products, and is light on the technical side.

The juicy bits are here, so you know what the fuss is about:

• Cytrix Netscaler (= loadbalancer with various optimizations)
• W2K8 + IIS7 and antivirus software on the webservers
• 650GB/day ISS log files
• 8-9GBit/s (unknown if CDN's are included)
• Simple network filtering: stateless access lists blocking unwanted ports on the routers/switches (hence the debated "no firewalls" claim).

Note that this information may not reflect present reality very well; the spokesman appears to be reciting others words.