If you have a 12 gig hard drive and you're only using 4 gigs then it's not a problem. But if you have a 4 gig hard drive and you need to put 5 gigs of data on it then this might help you. You can control the available size of the folder, first by keeping it within reasonable limits based on the amount of free disk space you have available. And second by clearing it out once in a while. Both things are accomplished from the same place.
Lets go to Settings first.
The first part of the Settings dialog box deals with when IE will check for new versions of stored pages. But this won't help you if the page changes while you are displaying it like the DumbAsk Message Board. The next area lets you set the amount of disk space to use for these temporary files. How much disk space you give it depends on some factors. The lower you set this number, the fewer web pages can be stored.