Asp.net Page output caching

i had read the answer i am unable to get understand what is this VaryByParam and what are its attributes. Please if u dont mine please try to explain it clearly

Output Cacheing

Give the following page a glance. This should explain the VaryByParams more clearly.

http://www.dotnetjunkies.com/QuickStartv20/aspnet/doc/caching/output.aspx

Basically Output cacheing will cache the page for a specific amount of time which reduces the number of roundtrips to the server. Generally if you have some static data on the page using output cacheing should reduce the amount of time the page takes to load. Using the VaryByParams will allow you to cache specific items on the page based on the parameters in the query string.

Nathan