\link{http://www.timesonline.co.uk/newspaper/0,,176-2208384,00.html\article here, especially second part}
My dd is five and still very innocent, but she doesn't seem much different to her classmates.
On the other hand I walked past a school playground the other day (not dd's school) where seven or eight year olds were discussing Big Brother. 
And I read about an eight year old in the paper who has repetitive strain injury from texting too much... had her first mobile at age six.
I'm just not sure what the "reality" is, and what's the exception.