Dynamic speed increases can be obtained with Fasterfox's unique prefetching mechanism, which recycles idle bandwidth by silently loading and caching all of the links on the page you are browsing.
http://fasterfox.mozdev.org/

Just from the description, it sounds evil to me. What happens when you hit a page
that has a big number of links. Not only are you needlessly accessing all those
servers, but wasting your own bandwidth. With four computers online,
there is no such thing as idle bandwidth in my household.


More...

It seems that there is evil afoot. I did a little more research on "prefetch"
and a lot of people are bitching about it. It apparently comes in two forms.
One is like fasterfox, and prefetches all links, unless excluded by robots.txt.

The other doesn't require the fastfox addon, but prefetches links designated
by the web page for prefetching. The plot thickens. It seems that Google
marks the top search result for prefetching, so your browser automatically
downloads the page, assuming that you would click that link anyway.

http://www.google.com/intl/en/help/f....html#prefetch

It probably distorts the statistics by generating extra hits on those pages.
No wonder people will kill to get top rating in a google search. Once you are on top
you get the artificial benefit of prefetch to keep you there. AFAIK, Internet Explorer
is not (yet) guilty of this behavior.