To add GNU Terry Pratchett to your own blog, go to your blog then click Edit theme and then Edit HTML. Copy and paste the following code into your theme.
<meta http-equiv=”X-Clacks-Overhead” content=”GNU Terry Pratchett” />
Then click Update Preview, then Save. Your theme will still look the same, but the code will now be a part of the page, so its always being sent and those with the right browser extensions will be able to see you have implemented it.