Inversive Phone Number Search
I just stumbled upon an amazing feature of Apple’s Addressbook in OS X. Though it is obviously not possible to search for phone numbers with spaces and quite often some partial numbers are not found at all; for example if you search for “567” the phone number “+49 89 45 67” will never be found!
But try the “inverse search”! Just type in the number starting with the last digit: “765” and the number will show up, ignoring all whitespaces. Just be sure to start with the very last number.
Acknowledgement goes to Uldis Melns who discovered this and shared in an Apple Discussion Forum: http://discussions.apple.com/thread.jspa?threadID=341724&threadrate=1&messageid=1650396#1650396