RIM recently removed popular messaging app Kik from the BlackBerry app store. The only reason given for the removal was "breaching contractual obligations". But according to a Canadian court filing, RIM has now sued Kik for patent infringement. It is not clear what features of Kik are considered infringing by Waterloo, but we would imagine it relates to the way Kik notifies users when a message has been sent, received, and viewed. Just like Blackberry Messenger (BBM).
Kik is available on several platforms, and has amassed a large userbase in the neighborhood of 2.5 million in a short time. Kik allows users to have an instant messaging experience that is closer to that of BBM than the competition. RIM may feel that BlackBerry Messenger is one of their remaining selling points as Android and iOS eat up the market.
Kik was in the midst of lining up a round of funding when this suit was filed. It's unclear if they were able to lock in any deals before the news broke. Kik founder Ted Livington is reportedly "disappointed" by the suit.