I spend my time to created extensions based on Gecko expecially for
- Firefox, Thunderbird and SeaMonkey (all under Mozilla umbrella)
Every product has its own developer website where you can upload your extensions (Komodo hasn’t a dedicated upload zone).
From a visitor/user feedback’s point of view Flock is the best.
Flock addons site is cool I love it, extension informations are very complete, you can see also the locales supported by extensions.
Songbird has a cool addons site simple and very quick, extension informations are complete.
Mozilla with AMO is the most important but is also the worst.
The outsider KomodoEdit addons site not yet really exists, registered users can’t upload their extensions.
I hope Komodo guys take a look at Flock addons site if they decide to create a similar place.
From a developer feedback’s point of view Songbird is the best.
After signup you can immediately upload and publish extension on Songbird site, the upload process is easy and publication policy very developer friendly.
AMO upload mechanism is simple but publication mechanism is awful. I don’t like its approval mechanism based on sandbox, my RichFeedButton waits approval for an year.
Flock allows to upload extensions immediately after signup but publication waits approval, after a couple of days I’m yet waiting😉
The most mature and important addons site AMO, has IMHO the worst user/developer experience.
I don’t like so much Flock but it has a great develope/user website