Since my post a couple of days ago about learning stuff, I decided to look at Greasemonkey. I've been meaning to do this for a long time. I kind of knew roughly what it did, but I found out properly, and wrote my own script.
Basically, Greasemonkey is a firefox extension that runs scripts on web pages shown in the browser. It allows access to the DOM, so you can modify a web page that you want to improve, but the owner won't touch it, because they're too lazy, too stupid, too busy or Google.
My biggest issue is with using Blogger as my blogging tool. I write out the post, and press the big orange button when I'm done, and Google then faxes my post onto my site and sticks them on my homepage. About two days later, if I get a comment, I might look at the post again, and realise that I've forgotten to put the technorati tags at the bottom of the post. Again. I've also forgotten why it's important to do this, but that's another story.
So, I tied these two things together in a pleasing way. You've already guessed what I did, haven't you? OK, so there's no need to tell you.