Some of the Reasons.
a-Security Leaving everything on Safe Servers is Best.
b- High Volume Standard Social Networking - Cloud Computing- Needs Standards
From Mobile Phones and Devices uptu Big Networks like Google, Facebook etc..
That need Fast Response and Standard Safe Internet Computing.
The "Net is the Computer" is Back again as Larry Alison likes to joke about "Cloudy Weather"...
The "Wars" Going on with Apple Ipad against Android Phones and Tablets with Amazon Wifi Kindles too. All Thin Clients!!!.
And Large Organizations like Health, Call Centers, Education are Safer and Saving Money with Thin Clients.