NEW YORK (TheStreet) -- News Thursday night that Japan's Rakuten was going to buy Cypress' Viber for $900 million was the latest sign that messaging apps are hot.

Rakuten is known as a giant of Japanese e-commerce and plans on increasing its reach into other parts of the world. It invested in Pinterest a few months ago.

Now it's bought Viber to beef up its presence in the messaging space. Clearly, Rakuten is worried that messaging is the next big thing since mobile itself came along. And they're right to be worried.

More specifically, they're worried about losing ground to Japan against Line. Line now has 300 million users and is most popular in Japan. If it continues to grow and develop, it could pose a real threat to Rakuten's core e-commerce business.

Rakuten is probably thinking that, if Line keeps building its audience and then starts to introduce new e-commerce services to that group, it could gradually bleed away users.

They're right to be worried. And they shouldn't be the only e-commerce company worried about this.

Alibaba needs to be worried about the increasing popularity of WeChat. Amazon (AMZN - Get Report) needs to be worried, too -- but they don't appear to be (or at least WhatsApp doesn't seem to have any ambitions to be anything other than the free messaging service that it is today).

But is Viber the answer to Rakuten's problems? I don't see it. Viber is more of a voice app than a messaging app. Voice calls appear to be a thing of the past rather than the future. Viber seems to be more designed to be a Skype competitor than a Line competitor.

Rakuten's CEO, Hiroshi Mikatani, said the deal was a "no brainer" as messaging was a hot space and Line was supposed to be worth something like $10 billion when it holds its expected IPO later this year. I think Rakuten also believes that it can take its own users and direct them over to the Viber app. So, they probably feel confident that they can make the app itself more valuable than what they're paying for it.

However, that thinking is flawed.

Viber is not part of the messaging app mix. And just Rakuten telling its e-commerce customers to start using Viber will not change that.

To me, the key players in messaging are WeChat, Line, WhatsApp, Line, Kik and Kakao. Rakuten would have probably been better off buying Kakao, which is mostly Korean-based and has seen its growth slowing. It probably would have cost more than $900 million, though.

If Line is worth $10 billion, so is WhatsApp. WeChat is as big as either of those apps and has helped Tencent double its stock price over the last year.

What's Kik worth with its 100 million users? Probably more than $1 billion. I'd peg it as close to $3 billion.

Kik is most interesting to me because it's been the most aggressive in embracing HTML5 and now starting to integrate third-party games as well as Web sites and search into its messaging platform. To me, that's the future. Kik is really trying to be the browser for the mobile-only world. It's not simply a messaging app. From the starting point of a browser, you can start to see the vision of where messaging apps are going and why e-commerce companies are worried about them. Now that's interesting to think about.

But Viber isn't anywhere close to that vision. It seems destined to be an also-ran in this white hot space.

At the time of publication the author had no positions in stocks mentioned.

This article represents the opinion of a contributor and not necessarily that of TheStreet or its editorial staff.

At the time of publication, Eric Jackson had no positions in stocks mentioned.

  Eric Jackson is founder and Managing Member of Ironfire Capital and the general partner and investment manager of Ironfire Capital US Fund LP and Ironfire Capital International Fund, Ltd. In January 2007, Jackson started the world's first Internet-based campaign to increase shareholder value at Yahoo!, leading to a change in CEOs in 2007. He also spoke out in favor of Yahoo!'s accepting Microsoft's buyout offer in 2008. Global Proxy Watch named Jackson as one of its 10 "Stars" who positively influenced international corporate governance and shareowner value in 2007.

  Prior to founding Ironfire Capital, Jackson was President and CEO of Jackson Leadership Systems, Inc., a leadership, strategy, and governance consulting firm. He completed his Ph.D. in the Management Department at the Columbia University Graduate School of Business in New York, with a specialization in Strategic Management and Corporate Governance, and holds a B.A. from McGill University.

  He was previously Vice President of Strategy and Business Development at VoiceGenie Technologies, a software firm now owned by Alcatel-Lucent. In 2004, Jackson founded the Young Patrons' Circle at the Royal Ontario Museum in Toronto, which is now the second-largest social and philanthropic group of its kind in North America, raising $500,000 annually for the museum. You can follow Jackson on Twitter at or @ericjackson.

  You can contact Eric by emailing him at