The immediacy offered by a website. Compare that to having to fill out a reader response card, or dial an 800 number. Pull vs. Push. People visit a website because they want to be there, just like they tune into television because they want to be there. But that's where the similarity ends.
People don' t choose to see television ads.
This is powerful. You can precisely measure how many visitors to your site have arrived from the Self-help and Psychology Magazine and thus can a pretty good idea of how effective your advertising is for any given week. The advertisers on television don't really know if a viewer changed channels at the commercial break, surfed to another channel or went to grab a bite to eat. Limits of space and time are gone. Now we're down to 30-second commercials on TV that don't even pretend to offer content.