I've been using Ubuntu since I installed the Hoary Hedgehog release in May, 2005.
Since then, I've been kind of active on the UbuntuForums and have written a good deal about Ubuntu on my blog, even having some success in converting friends and relatives to Ubuntu. I signed the Ubuntu code of conduct, and you can find my (still somewhat empty) Launchpad page here: https://launchpad.net/people/agger
Right now, I'm a bit too busy with my day job and my blog at http://www.modspil.dk, but at some point I hope I can get more involved in Ubuntu-related projects.
Apart from the occasional forum post, my main Ubuntu-related activity has been advocacy, primarily on my blog, of Ubuntu as well as of free software in general - if you read Danish, you could take a look at my blog's two IT-related "channels", http://www.modspil.dk/itpolitik and http://www.modspil.dk/itogtech/ or search for the word "Ubuntu" in my blog posts. I also participate in the mailing list and IRC channel belonging to the Danish Loco team.
I expect to continue doing this. And while many other free systems are excellent, Ubuntu is clearly the system to recommend to ordinary users - so this is what I expect to continue doing.