I bet HP does that as well, but doesn't have as much at stake if your actual contacts or emails are leaked publicly.
Originally Posted by Maverickz
Google gets almost 100% of their revenue by people trusting them with information. If you're comfortable with how they use that information (which obviously you are not), then you can be assured that they are not going to allow it to be leaked publicly (since that would destroy their whole business in one fell swoop).
If you're not comfortable, then yes, you definitely should run your own servers.