How much is the telecoms industry losing to chat apps?
Instant messaging conducted over so called "chat apps" has overtaken more traditional text traffic.
More than 19 billion messages a day were sent via apps - such as Skype, Wechat and Whatsapp - in 2012, compared with 17.6 billion SMS texts.
One estimate suggests the telecoms industry is losing around $100m (£59m) a day to Skype alone.
So what are mobile operators doing to stem the loss of revenue?
Mike Ropicky, Asia Pacific Vice President of the telecoms information provider Tektronix Communications tells the BBC's Rico Hizon.