People are extremely task-focused on the Web. That means they are much less open to content that is not directly related to the task at hand.
I've just read a very interesting study, "Memory for Advertising and Information Content: Comparing the Printed Page to the Computer Screen" (Psychology & Marketing, August 2005).
A key finding of the study is that "print is consistently better for recall than screen.... The central theme to emerge from this study is that individuals have a better ability to recall after viewing materials in print rather than on screen."
This is not surprising. Various studies have found that it can be 20-30% more difficult to read from a screen than it is from print. The Web has thus become a very functional place. People get on the Web not to vacation but to find cheap flights and hotels for their vacation.
"Brand-name recall was substantially lower for screen respondents," according to the study.
Again, this is not surprising. Google has built a major business by selling advertising that relates directly to what people are searching for. There is not a single banner ad on Google, not a single graphic trying to enhance brand recognition. Google knows its audience. It knows what works and doesn't work on the Web.
"Information content viewed on a screen is nearly as likely to be remembered correctly as the same content in print form," the study finds. By "information content," the study means content that is genuinely useful to the reader—content that supports the task at hand.
The study goes on to state, "It seems entirely reasonable to believe that the Internet will do a good job disseminating time-dependent or other important factual information about products and services."