I received one piece of feedback from someone who read my blog via Planet Debian, but didn't appear to email me from a usable email address, so I'll respond to the criticisms here.
I wrote a Chrome extension because I use Google Chrome. To the best of my knowledge, it will work with Chromium as well, but as I've never used it, I can't really say for sure. I've chosen to licence the source under the Apache Licence, and make it freely available. So the extension is available to anyone who cares to download the source and "side load" it, if they don't want to use the Chrome Web Store.
As for whether a userscript would have done the job, maybe, but I have no experience with them.
Basically, I had an itch, and I scratched it, for the browser I choose to use, and I also chose to share it freely.