Signs of consumers moving on from text-messaging to social media, email and IP-based messaging systems started cropping up in 2011 in advanced SMS markets like Netherlands and Philippines. What we seem to be witnessing is a situation where those countries where SMS took off first during Nineties are now the first ones to see a steep decline in SMS usage.
In Hong Kong. the Christmas Day text message decline was nearly 14%. It does seem as though the SMS erosion rates in countries that originally pioneered the service are higher than most observers anticipated in early 2011. Possibly because new services such as mobile Facebook and Twitter are now widely adopted in the same markets where SMS took off after 1995."
Source: Forbes, 29th December 2011