We care about your security, that's why MessengerDiscovery will encrypt your instant messages with contacts that have MessengerDiscovery.
You don't have to do anything, enabled by default - your Messages will be trasparently encrypted to any other MessengerDiscovery users.
This solves a big problem as Windows Live Messenger sends your messages in plain text! Your messages are easily read by hackers or by anyone who can access the data transfered by your computer (ISP's, Governments etc.).