Business
HTML Validator is one of my most favourite Firefox web browser add-ons. You can probably guess from the name that it validates HTML. Useful. However, it doesn't work in Ubuntu 9.10 Karmic Koala.
Luckily Benjamin Drung has made a workaround. Simply add his PPA to your system, then install htmlvalidator using Synaptic Package Manager. Thank you Benjamin, much appreciated.