This is the first time that BlackBerry software has been available on other smartphones and marks a radical shift in the management of the Canadian-based manufacturer. From 2012 onwards, BlackBerrys have gradually been dropping in popularity - the latest statistics show that BlackBerry OS worldwide accounted for just 3.7% of smartphone usage in July 2013, compared with 38.3% for Android, 24.8% for iOS and 14.4% for Nokia's S40 platform.
No it's not. A few years ago RIM offered BlackBerry Connect for use on Palm, Nokia (Symbian) and some Sony Ericsson devices.
These devices were assigned a PIN that you also found on standard BlackBerry devices so that email and some policy enforcement on devices.
As BBM is PIN-to-PIN (historically) they are likely following the same principle.