It has been over a year since a Google Calendar service was first hinted at, but it seems they have now started beta-testing a product called “CL2” (screenshots here).
To repeat my original privacy-related concerns, Google is moving more and more towards building a broad information infrastructure which requires setting up accounts which link personal information across services. Doing this allows Google to aggregate all your personal content (Gmail, calendar entries, etc) in order to not only provide you a more personalized search experience (perhaps a good thing), but also to deliver you more personalized advertising (perhaps a good thing, perhaps not). In all, this again raises interesting value implications (privacy, autonomy, etc) of the Googlization of more and more of our lives.
MichaelZimmer.org 
When I read George Dyson about Google creating an “artificial intelligence” this started making more sense. They need all human information processing to be able to build their AI… Thus also a calendar.
“Human information” can be collected from many Google-related services: Gmail, Google Talk, Google Reader, Picasa, Blogger, Orkut, Desktop Search, etc….