Messaging apps are proving popular across the globe; indeed, WhatsApp CEO Jan Koum recently claimed that his service is bigger than Twitter. And a new study by Informa, on behalf of the Financial Times, concludes that chat apps have overtaken traditional SMS in terms of message volume. By the end of 2012, there were more messages sent via iMessage, BBM, WhatsApp, and Kik when compared with regular texting. Because SMS has been a traditional resource for wireless carriers, this trend has been worrying for these companies. By the same token, however, SMS is still far ahead in overall user count, and Informa expects providers to pull in $120 billion from texting plans this year. Ultimately though, non-text-message output is expected to reach 41 billion per day in 2013, which is double the number of forecasted texts; WhatsApp already reportedly processes 18 billion messages each day alone. Ultimately though, if carriers want to monetize messaging like texts, it remains to be seen if users will stick around.