The only thing I wonder is WHY?
I mean, there are enough chat app's that are availible for more companies (eg Whatsapp, wich you can use on iPhone, Blackberry and Android) that are simmilar to BBM.
Here, in The Netherlands, all 12 yr olds (yeah I know, creepy to see) are walking around with Blackberry BECAUSE of BBM. They dont get the concept of what a blackberry can do / is besides BBM.
So if you would allow BBM to be used on Apple or Android, you will miss out on a whole group that will go and get some other "trendy gadget" like an iPhone because you are loosing an argument to get a Blackberry.
"Why don't you get an iPhone?" I want to ping. "Well, BB was in a drunk mood and released BBM on iPhone aswell" So you mean I can have that sweet *** interface with 32GB memory, a big screen to watch movies on, play cool games, a cool MP3 player AND have BBM? "Yes you can" Oh well, Ill have the white one then...
Id never trade my BB for anything, but there is a big group that is sensitive to trends and would switch from brand A to B in the blink of an eye because they found something they like. BBM is what keeps RIM apart from the rest for this group.
I think its a bad idea, even if it´s a stripped version.
My posse agrees::ernie::::cookie::::thecount::::elmo::::big bird::::kermit::::grover:::

scar::::bert::