While the Hummingbird icon was well balanced and indicated motion, there were a few reasons that made us change:

- We didn't feel it was Mac OS X-y enough; it didn't seem to fit in with other icons in my Dock.

- The concept itself was too abstract. Given our product name is also abstract, we wanted something a little more concrete. The new concept is an animator's lightbox, which we felt is closer to its purpose. Admittedly not a lot of people have seen this in their lives...

- We wanted some way to convey the HTML5 given its importance in our app.

- Everyone is doing birds nowadays!