Looks like guzzoni.apple.com is named after Didier Guzzoni (http://www.ai.sri.com/~guzzoni/), an employee at SRI.

He's also listed on an interesting Apple patent that was only filed a few weeks ago, "INTELLIGENT AUTOMATED ASSISTANT"(http://www.wipo.int/patentscope/search/en/WO2011088053).

Some very interesting implementation details there.