Does online have a shorter shelf life than it's counter parts

In my view online is a bit hit and miss when it comes to shelf life, I do believe that in order for online work to have a better shelf life you need to make it work a lot harder for you.

What do I mean?

Well with and offline material you will have the users undivided attention (how ever long that may be) and it's at points where they can't really escape. With online you need to direct and entertain your user whilst not boring them, they want to see motion, they want sound and they want to be told.

Why is this the case?

This is the entertainment age we all want to see and hear something astounding, the message is clear it requires less effort for the user and to keep it fresh you need to be able the generate content.

So how does this relate back to the question. Simple. You have 20 seconds of my time, your job is to keep me interested past 20 seconds. What do you do?