Understand the medium: The web is not like print media

There are many goals for using the web: information, shopping, communicating, playing, advertising.
Investment of time in every action.
No way to "flip through" quickly.
People read differently online than with print media or multimedia.
People don't make optimal choices online. They satisfice (low penalty for guessing wrong).
The web is available worldwide and presents information virtually instantly.

References:
Krug, Don't make me think: A common sense approach to web usability, 2000.
Nielsen, Reading on the web, 1999.