But BBM was limited and only available for BlackBerry phones, so if your friends wants to use BBM they need to switch to BlackBerry. but now BlackBerry has announced that they are going to release an BBM app for iOS and Android.
In first edition of BBM for Android and iOS users will be able to do :-
Voice note sharing
BlackBerry Groups, where BBM users are able to set up groups of up to 30 people and share calendar, photos, files and more.
BlackBerry has said that BBM will be available by this summer, however it is subject to approval from Google Play and Apple Stores.