Using AddressBook to share information between iPhone apps

I've read that it's possible to share information between iPhone applications using the Addressbook. In fact, TextExpander Touch seems to be able to do just this by looking at their SDK how-to:

http://www.freshblocks.com/tutorials/how-to-add-tex开发者_JAVA技巧texpander-touch-sdk-to-iphone-apps/

Can anyone provide a concrete example of how this is achieved? I've read that it involves creating a 'dummy' contact - but I don't see any such dummy contacts on my phone.

I would instead use inter-app communication using custom app URLs ala: http://mobileorchard.com/apple-approved-iphone-inter-process-communication/

I would imagine polluting a user's address book with dummy contacts would be severely frowned upon by Apple/rejection-worthy.