OK...hands up, how do you read a book and surf the web? Interesting research from Burst Media. Surprised driving a car isn't in there myself.
Surfing the web over a low-bandwidth/high-latency satellite connection leaves plenty of time for reading a book while waiting for your page(s) to load...
Also it just says "online", not necessarily "surfing the web".. ever been in a World of Warcraft raid? :) I know people that have finished novels during Molten Core....
Slight curveball, but there was an interesting study earlier this year that turned assumptions about our reading habits upside down. Conventional wisdom has been that the Internet is turning us all into short-attention span stress bunnies. Turns out that, when something grabs our interest, we often read more online than when reading paper equivalent - http://www.joiningdots.net/blog/2007/03/attention-span-myths.html