Google App Engine

Google App Engine gives you access to the same building blocks that Google uses for its own applications, making it easier to build an application that runs reliably, even under heavy load and with large amounts of data

So they can get at your data and know everything about your website.

Dynamic webserving, with full support of common web technologies, Persistent storage (powered by Bigtable and GFS with queries, sorting, and transactions), Automatic scaling and load balancing, Google APIs for authenticating users and sending email, Fully featured local development environment.

Seems powerful enough.

Google App Engine packages these building blocks and takes care of the infrastructure stack

Nice

During this preview period, applications are limited to 500MB of storage, 200M megacycles of CPU per day, and 10GB bandwidth per day. We expect most applications will be able to serve around 5 million pageviews per month. In the future, these limited quotas will remain free, and developers will be able to purchase additional resources as needed.

That's pretty large.

Link:
http://googleappengine.blogspot.com/