An aside: Mozilla's approach to Firefox extensions is both 1) responsible (they require extensions to be reviewed and signed by Mozilla), 2) untenable for developers (mine took forever to be reviewed).

I published three Chrome extensions last year, and decided to port my more ambitious one to Firefox. (all at http://www.metafruit.com) Now I feel somewhat bad for complaining since I'm not an extension reviewer myself, and I feel they've taken on a tall order for the betterment of their community. But my Firefox port took four months to get to the front of the review process. Needless to say, my next extension is targeted only for Chrome.

Chrome's approach is easy for developers but almost reckless for end users.