[shalinmangar]

Whatsapp is hugely popular in India where phone contracts are not popular and most people use pay-as-you-go prepaid mobile services. Very few, if any, of them come with unlimited messages. Unlimited messages are a US-only thing I guess.

[k-mcgrady]

I'm in the UK. That doesn't change my point though. Despite the unlimited text messages in UK/US people still use Whatsapp.

[daledavies]

My 2 cents...

Group text via SMS is a PITA. The main reason why I use WhatsApp for certain messaging tasks.

Having Wifi but no phone signal - WhatsApp gets used again.

WhatsApp also lets you see when a message has been received and also when it has been read. Spooky, but useful.

[jhasse]

WhatsApp has lots of features which SMS don't.