WhatsApp Messenger claims it's the easiest way to keep your contacts closer across all smartphone platforms. It does take only a few seconds and 99 cents to get it set up, and then you are ready to send unlimited text messages, photos, audio notes, and video content to your favorite contacts just by using your Internet connection.
The app has pretty good Yahoo Messenger-ish characteristics, as implied by its name, but the thing we liked best was how it handles messages. WhatsApp Messenger uses push notifications to deliver the messages your friends have sent to you, keeping you up-to-date.
We found WhatsApp easy to use, and its simplistic design with multiple Address Book elements gives easy access to the available message delivery tools. During our testing the app performed very well, without any flaws or error messages. The text was delivered instantly and we were reminded that the app supports real-time chatting by informing us when the other person was typing to respond to us. We were also pleased to find that even after we closed the iPhone or entered a place with no network coverage, we received the messages via push notification, as soon as the Internet connection was established.
WhatsApp can easily change the way you text, and the temptation to dump your SMS message plan is very high, as it carries no additional cost. The app is ready to use in seconds, as it uses your phone number and doesn't require any username and password. The only drawback we could find was that you need to invite all your friends to join this network in order to use it to communicate with them while on the go.