Interesting. I had considered writing some addons as a possible alternative to mobile app development for a little extra income but I gave it up because I assumed it wasn't viable. Glad to hear otherwise.
It's likely far less lucrative than mobile apps. I've got some exceptionally popular addons, but they aren't going to make me rich. I suspect the average developer with low-to-medium visibility addons doesn't make very good money with them.
(I've been meaning to get into mobile app development; I've written a free Android app, but I can't seem to come up with a good concept for something I could charge for)
