Another great way that the Internet gets what it wants is with the Greasemonkey extension to Firefox. It lets you automatically add to the Javascript on pages of your choice.
I wrote a script to suffix "open new" onto RequestTracker searches, as version 3.6's quick search box seems to show you all the tickets, even the ones that have been resolved for three years. You will need to change the sites this applies to to match your own.
Today, a workmate asked for my Expert-Sex-Change login, to get around the ROT13 and blurring they now put on their answers if you're not signed up. (Cheatin' bastards want Google juice for it, be prepared to show it to everyone.) "I bet someone's written a Greasemonkey script for this", I exclaimed, and lo, they had. I reproduce it here with a nice little click-to-install as the author's WordPress eats the quotes.
By the way, if you do any web development at all (and I don't do very much - just tidying things up), install the Firebug extension. Right now. It's fantastic. We do everything through this. Everything.