I heard about this survey also, this weekend, and I laughed. I definitely think that Steve Outing has the right perspective on the ridiculous results of this biased survey.
And I wouldn't be surprised even if a "fair" survey under-counted "the internet" as a source of information used when making purchasing decisions.
First, most people don't KNOW why they do many of the things they do. Second, many people don't want to ADMIT how they made a decision -- they may feel embarassed.
Lots of people won't admit that they met someone through an online 'personal ad.' (I met my wife through a 'personals' ad she placed on CraigsList.org.)
When I was an estate-planning attorney, I had a listing in the Yellow Pages, but not one client EVER admitted that they found me in the phone book. There were a few clients that I was quite sure had found me that way, and many others who could never explain how they found my name.
After I started promoting my estate-planning practice on the internet, I gained a number of new clients who had never used the internet, but whose adult children had found me online and gave my contact information to mom or dad, often along with a copy of an article from my web site.
I believe that 90% or more of Neilsen's revenue comes from TV and radio (and ad agencies that produce TV and radio commercials), so I would expect this survey to be strongly biased in "favor of" those industries.