iMessages

[j_maddison]

They still could. They are opening up iChat to third-party plugins.

Awesome! I didn't know that

 

[BergerFan]

Integrated is the key. I know lots of people with iPhones and not one with whatsapp. BBM is so big because everyone has it, no extra work needed.

That's it. You can't beat the power of a baked-in solution.