I received this response from Rovio regarding my inquiry about Angry Birds:
Mark,
thank you for contacting us.
We take our users' privacy very seriously.
Angry Birds does not access your contact information. If you have registered with Crystal social gaming platform, you can select to find friends using Crystal by searching from your contacts. Crystal matches the email addresses in your contacts with email addresses of registered Crystal users. No contact information is collected or stored by Crystal.
If you have not registered to Crystal social gaming platform, this option to use contacts to find friends not available, and no contact information is used in any way at all. For more information, see the Crystal Privacy Policy. To access the policy in Angry Birds, select the Crystal icon, and select Account Settings > Crystal > Privacy Policy.
The above stands for current location information as well. Unless you explicitly select to use the information in Crystal, neither contact or current location information is used for any purpose.
I hope this clarifies any concerns.
Best Regards,
Ville Heijari
Bird Whisperer
Rovio Mobile Ltd.
That's good enough for me. I don't use the Crystal social gaming system.
Mark