BlackBerry will this weekend take a historic fork in the road as it makes what was once its distinguishing application, BlackBerry Messenger (BBM), available for download to Android and Apple smartphone users.Announced as an intention several weeks ago, Android 4.x users are expected to get access to the app on 19 September at 12 Noon BST from Google's Play, followed 12 hours later fro iPhone users from Apple's App Store.The move is an extraordinary moment for Blackberry and given that BBM messaging will be free also between users running the app, potentially disruptive for the mobile market as a whole if it can grab new users. There are currently no plans for a Windows Phone app.The firm's strategy of turning BBM into a larger social platform explains why it has taken the interesting if risky decision to untether its messaging system from its own declining hardware and software platform."Later this year, BBM Channels will provide a forum for active, real conversations between y
