Jan Koum, CEO of WhatsApp, has no intention of building an app for desktop computers. WhatsApp is arguably the most successful independent mobile messaging app in the world, so Koum's views have some credibility, but what if mobile is only one half of the messaging puzzle? Viber CEO Talmon Marco is betting big on the desktop with today's launch of Viber for PC and Mac. The app includes video chat and voice calls, like Skype, and syncs all your messages instantly with the company's mobile app across BlackBerry, Windows Phone, iOS, and Android. In a messaging world that feels increasingly mobile-first, Marco's hoping that building apps for every platform will win out. At 200 million users as of today, Viber's already off to a good start.

Viber for PC and Mac feels like a more modern version of Skype mixed with Messages for Mac. All of your contacts fill a left rail, while text and photo content are ordered chronologically on the right. You send text messages to friends, place voice calls, and also engage in video chats. Everything is synced instantly to Viber for mobile devices, which Apple's Messages still struggles with. While the app can't yet do conference calls or mobile-to-mobile video calls like Skype, it boasts some innovative features like the ability to pass off calls from desktop to mobile and vice versa with one tap. Marco is quick to point out, however, that Skype began on desktop while Viber began on mobile — a platform that he affirms is still the most important.

Everything is synced instantly to Viber for mobile devices, which Apple's Messages still struggles with

Viber for PC and Mac is most impressive simply because it acknowledges that many of us sit in front of computers all day, so typing on a 3.5-inch screen isn't always convenient. Yes, there are several ways to message friends from a computer, such as email or IM, but few apps aside from Skype let you easily send rich forms of content and place calls. It seems increasingly likely that we'll have to choose between multiple ways to message friends — especially since most leading messaging apps seem content with operating only on mobile devices — but now that Viber's on Mac and PC (with Linux on the way), Marco hopes you won't have to.