https://addons.mozilla.org/extensions/moreinfo.php?id=1269&vid=6436
"Enhanced Prefetching takes all of the links on a webpage and adds them to the queue to be prefetched in the background. This way by the time you are finished reading one page, the pages linked from that page are already cached."
This is potentially a very bad thing ?
Yes pre-fetching is often hotly debated and I really can't see an intelligent way to implement it as it is going to load plenty of stuff you don't want it to load including advertisements and sites that may not be safe for work plus if everyone had pre-fetching on when they were reading your home page it would really chew into your bandwidth!