From the article:

The Microsoft patent uses partial licenses, consisting of both a public and a private key, to provide customers with the right to decrypt the content they access over the peer-to-peer network.

So it's a combination of two things:

• Secret Splitting
• Superdistribution

And for this they have been granted a patent? *le sigh*

I quote the team from memory (I just returned from CCC):

Removing or disabling all certificates where a MD5 signature was used somewhere in the chain (or was that just for those that had intermediate CA's signed with MD5? - anyhow...), would cripple approximately 30% of the entire internet.