SMS texts, no need to force the other person to install an IM app, nobody on my contacts has even bothered with BBM for example but a few of them uses Skype and a few others uses Google chat or Facebook chat (which I don't use), etc. IM is far too fragmented, and SMS is available to everyone and mostly unlimited these days.
I use blackberry Messenger because of security. Some people who do not have bbm I text to them.I always text. To me it's more formal and reliable.
I don't know anyone on BBM any more. Too bad because it had potential.I use blackberry Messenger because of security. Some people who do not have bbm I text to them.