Prefetching will fetch links on your browsing page as if you had clicked on them yourself and put those pages into your cache.  When you are ready to choose a link on your page, it may already be in your cache.  The longer you read the page you've got, the more links are cached.  The links you don't follow today will still be in your cache waiting for you tomorrow!

We do not have prefetching "on" by default so that those who pay their Internet Service Provider for the number of web pages downloaded aren't surprised by huge bills.   If you pay a fixed monthly fee or pay by the hour, we highly recommend using prefetching.

If certain sites present prefetching problems you can deal with them individually in the Exclude.txt file.  Look for "Site-Specific Options" in your Webcelerator Help file.