Instant messaging on chat apps, such as WhatsApp, has overtaken the traditional SMS text message for the first time, according to research firm Informa.
Informa said almost 19 billion messages were sent per day on chat apps in 2012, compared with 17.6 billion SMS texts.
The shift is likely to have a big impact on mobile operators, for whom texts have been a key revenue source.
Pamela Clark-Dickson of Informa said some operators were already “seeing a decline in their messaging revenues”.
According to separate estimates by research firm Ovum, more than $23bn (£15bn) of SMS revenue was lost in 2012 due to popularity of chat apps.