Earlier this year Blackberry announced that it would make BlackBerry Messenger (BBM) available to iOS and Android devices. Many people suggested it was too late as services like What's App have already gained traction.
BBM is expected to be available to the public in September 2013.
With so many services now offer the same thing who will win the market and become established as the leading service provider. What's App is available on every device with BBM only on Blackberries but adding iOS and Android next month and trailing behind is iMessage, Apple's free messaging services.
iMessage has a great advantage in that it is built into iOS and can determine if a message should be sent as an iMessage or an SMS. this makes it simple for the user who doesn't have to worry about how to send the message. Hopefully someone will integrate all these great services.