Along with fintech, messaging apps today represent one of the hottest sector with large companies which compete globally. By acquiring Whatsapp for approximately $19bn (read here) in February 2014, Facebook (nasdaq: FB) seems to have taken the lead to win the race. But who is in the game? Which are the best positioned apps and, overall, how do they make money? Some time ago, speaking with a top European venture capitalist, I argued that - for a lot of these apps - I couldn't see a clearly defined business model. He answered me by saying "You cannot see that because they don't have any business model". A complicate question, even considering that a big number of users is not directly proportional to the amount of revenues they generate. - Restart from WhatsApp, which allows 400 million of users worldwide to send and receive messages, pictures, audio notes, and video messages with friends and family. They found a simple business model with the app free for one year and then costing $.99 per user per year. - Some weeks before the acquistion of it, Rakuten, Inc. (JASDAQ:4755), a Tokyo, Japan-based Internet services company, had bought Viber Media Ltd, the Limassol, Cyprus-based messaging and VoIP company, for $900m (read here). In that case, while reading the press release, I immediately noticed that Viber didn't have revenues in 2012 while they amounted to approximately $1.5m in 2013. Only last year, they planned to sell stickers, clipart-style emoticons and text to try to generate revenue. At the time of the transaction, Viber had approximately 280 million registered users and over 100m monthly active users worldwide. - In Asia, the biggest challenge comes from WeChat , which offers a free-to-download mobile app (available for Android, BlackBerry, iOS, Symbian and Windows Phone operating systems) to reportedly about 300 million active users. Following three monetization attempts, they released the 5.0 version of the platform in 2013, which includes mobile games and stickers, as well as tools for Chinese retailers to create their own online stores on the platform. According to estimates by Barclays, the company is expected to earn $1.1 billion in 2014 and about 40% more in 2015. - In the same area, another big player is Nippo-Korean Line, which offers a free app to share photos, videos, voice messages, contacts and location information with friends. The company generates revenues via stickers, which can be included in chats, and in-game purchases in videogames, downloadable for free. With approximately 350 million users, it had $120m in revenues in 2013, more than fivefold compared with 2012. - Evan Spiegel's SnapChat, which allows users to "snap" photos or videos that disappear quickly from the screen, became famous for having reportedly rejected a $3 billion takeover offer from Facebook in the end of 2013 (read here). With an undisclosed user base and a team of 15 developers, the LA-based, venture-backed startup is now trying to generate revenue via advertising and virtual goods. New meaningful market players include Telegram, Whisper and Secret, among others. Given the above, it looks clear that the biggest players in the messaging sector have succeeded in attracting an enormous quantity of users, often supported by venture capital investors. The true challenge is now finding the right business model in order to extract the highest value from any single user. The experience shows that monetizing by selling the app represents only one of the possible options. Try to diversify streams, by adding, for example, stickers, virtual goods, games, in-game purchases can be crucial to augment revenues and skyrocket valuations.