Cross-platform mobile messaging apps are on the rise, and we’ve actually featured a few here on e27, including LINE, KakaoTalk and WeChat, among others. Notably, LINE has recently surpassed the 100 million user mark, and the service is said to be growing in Hong Kong, doubling its user count each day.

LINE has reported doubling its user base each day in Hong Kong since the past week, and this can be attributed to the move by local carriers to charge extra for inter-network messages. In Hong Kong, SMS messages sent within the same carrier are typically free, although messages sent to other networks are charged a fee.

BeSuccess notes that messaging apps that are popular in Asia would usually include voice calling and other added features, on top of cross-platform messaging. For instance, WhatsApp only offers IM, while regional apps like LINE, KakaoTalk and WeChat would offer voice calls, as well as stickers, stamps or emoji, which have become one of the main sources of revenue for these developers. To illustrate, LINE earns about 350 million yen (about US$ 3.73 million) monthly from its in-app purchases, as of late 2012.

What makes messaging apps click?

As a smartphone user, messaging apps like LINE are a boon for me for several reasons. First, there’s cross-platform compatibility, which means I’m not limited to messaging with users on the same OS, like iMessage for the iPhone is. Then, there’s cross-device compatibility. I can chat with LINE users on the Mac or PC. There’s also the benefit of being able to message colleagues and friends from across the globe without extra cost, whereas international SMS messages are charged a premium by my carrier.

SMS is on the decline, and carriers might be trying to find ways to keep monetizing this 20-year old technology even as social media and cross-platform messaging apps are on the rise. Will apps like LINE accelerate the decline of SMS?

LINE is run by the Japanese division of South Korea’s NHN, which runs the top Korean search engine Naver. Other developments related to NHN and LINE include the recently-launched Undead Slayer and the rise of LINE’s social gaming platform.

LINE is a free download on the iTunes App Store and Google Play Store. Other platorm downloads are also available through LINE’s website.