It's called WhatsApp plan, a prepaid mobile plan to allow users surf the web and send email and instant messages. It's for those who do not have a data plan for their mobile line.
Of course, with this service, a user can use the popular Whatsapp messaging service to send instant messages to others without incurring SMS (Short message service) charges. That's why the name Whatsapp plan. The terms for Whatsapp usage include fair usage of 1GB per day and for use within Singapore only. Yet it claimed a user can use it to send and receive messages, images and video with no extra data charges.
Before Whatsapp became available, the only messaging service we have on our mobile phones is SMS. Most mobile subscription plans will come with a limited number of free SMS. Any SMS sent above the free ones will be charged at 5 cents per SMS. Those users who used to SMS frequently must have paid through their nose on those years.
This reminded me of a news I read about Singtel and StarHub's (another mobile operator in Singapore) plan to launch their own messaging service to counter Whatsapp, which has been responsible for the declining usage of SMS and revenue for the operators.
Singtel must have discovered that instead of developing their own messaging application, it's easier to collaborate with Whatsapp. It's a cheaper alternative too.
But getting people who haven't use Whatsapp to pay $6 per month, or rather $72 per year to use it is a big challenge. Those who need Whatsapp are probably already using it. Those who are still not using it will probably never need or want it.
$6 is enough to send extra 120 SMSes; 1440 SMSes for a year.