I've posted this before but since some people are having trouble with the Adblock plugin for microb, I thought I'd repost this:

Ad blocking with css:
http://floppymoose.com has a good file (doesn't get everything though).

Save the file userContent.css to /home/user/.mozilla/microb/chrome/userContent.css to enable blocking with that file.

Restart browser once you have the file in place. Make sure permissions and ownership are set right.

This solution is very fast and very easy to setup.