6 Great Skype Alternatives

Mobile device users sent an average of 36.6 billion messages per day throughout 2012. Not all of them were text messages, however. In fact, fewer than half were routed through traditional, carrier-based SMS services. Analyst house Informa says that 19 billion messages were sent each day from mobile chat apps, while 17.6 billion were sent via Short Message Service.

In its report, published by GigaOm, Informa predicts that the scale will be even more imbalanced next year, when mobile chat app users will send 50 billion messages per day compared to 21 billion text messages per day. This is a seismic shift for the industry, as SMS has been a solid revenue source for years.

U.S. carriers often charge customers who don't subscribe to a messaging bundle between 5 cents and 25 cents per text message. The more messages you send, the more you pay at the end of the month. This is why they also offer messaging buckets, which typically cost $5, $10, or $20 extra per month for some preset number of messages (up to and including "unlimited"). Some carriers, such as Sprint and T-Mobile USA, include unlimited messaging in their basic voice, messaging and data plans. Any way you look at it, mobile phone users pay more to send messages via SMS. That's why so-called over-the-top apps have become so popular.

[ When you do send a message, do you type with your thumbs? Read All Thumbs? Tablet Keyboard Promises To Help. ]

Over-the-top (OTT) apps are third-party messaging services that don't use the carrier's SMS delivery system and instead push messages through the mobile device's data connection. These OTT apps let users avoid SMS fees. Informa points out that the chat app users are sending an average of 32.6 messages per day, while SMS users are sending an average of 5 texts per day. It's easy to understand why.

What are these OTT mobile messaging apps, and where can you get them? Many smartphones have them built in, and others are available from BlackBerry World, the Google Play Store, the iPhone App Store and the Windows Phone Store, among other places. Some of the more popular include BlackBerry Messenger, ChatOn, iMessage, Facebook Messenger, Google Talk/Voice, Kik, Skype, Viber and WhatsApp.

They're not all created equal. Some work only with other devices running the same platform, while others only work with devices using the same app. Here's a quick rundown on what each does.

BlackBerry Messenger is BlackBerry's age-old messaging service. It goes back 10 years or more and uses BlackBerry's messaging servers to deliver messages directly to other BlackBerry users, completely avoiding carrier SMS services. It works only between BlackBerrys.

ChatOn is Samsung's mobile chat app, but unlike BlackBerry Messenger, it is not limited to one platform. In fact, Samsung has released versions of ChatOn that work with BlackBerrys, Android smartphones, the iPhone and even Windows Phones. In order to chat between an iPhone and a Galaxy S 4, however, both devices need to use ChatOn.

Apple's iMessage is for Apple devices only. It lets iPhone, iPad and iPod Touch users send messages back and forth through the devices' data connection. On the iPhone, messages that can't be pushed through iMessage (for whatever reason) are delivered via SMS as a back-up.

Facebook is pushing hard to be the mobile messaging platform of choice for many users. It fact, it recently updated its Facebook Messenger app to include a unique new feature called Chat Heads. Like ChatOn, Facebook Messenger is available to a wide variety of smartphones (Android, BlackBerry, iPhone, Windows Phone) and works with any other device (including tablets and PCs) that has Messenger installed.

Google actually has three OTT mobile chatting apps. Google Talk is the instant messaging apps that's been available to all Android smartphones almost since day one. It works between Android smartphones, tablets and desktop-based browsers. Google Talk shares its base functionality with Google+ Messenger, which is a separate chatting app that hooks into Android users' Google+ accounts. Android devices typically have both Google Talk and Google+ Messenger installed. Google+ Messenger also functions from within the dedicated iPhone/iPad version of the Google+ application. Google Voice is entirely separate and is available to both Android and iOS devices. It is meant more to serve as a calling service, though, and its messaging function is rudimentary at best.

Kik and Viber are similar to ChatOn in that they are cross-platform apps that require people to use the same app in order to communicate back and forth.

Most mobile professionals should be familiar with Skype, which not only powers free Skype-to-Skype messages, but also VoIP-based phone and video calls. Skype is a cross-platform service that is available to Android, BlackBerry, iOS, and Windows Phone devices, as well as tablets and desktops.

The last of the major OTT mobile chat apps is WhatsApp, which has seen phenomenal growth in the last year. As with ChatOn, Kik, Skype and Viber, it requires that two people have the app installed in order to converse with one another. It is popular because it works with a wide range of smartphones. WhatsApp recently claimed that it has more daily users than Twitter.

The problem with all these services is that none of them can completely supplant traditional text messaging. SMS may be old and clunky, but it works with every mobile device on every carrier. Rather than replace SMS, mobile chat apps should be used to supplement SMS and get around it when possible.