All it does is boost your page request/second. When you open up a new webpage, FF requests that page a few times, to speed load time up a bit. What that extension does is change the following parameters for you so it requests page information more often.
network.http.pipelining
network.http.proxy.pipelining
network.http.pipelining.maxrequests
All it really does is waste the host's bandwidth so you can see the full page a 1/2 second faster. Its an old trick, and it works, but it really isnt good for the server, especially if everyone uses it and hits the same server at once.
Its like a kid tugging on his moms skirt cause he wants icecream. Now put that kid on crack......