I'm the creator of Zircle UI and I'm currently working on Zumly, which is a step forward to create zoomable web apps.
The main features of Zumly will be:
Zumly is an open source project, but will remain private until it reaches a certain degree of maturity.
In the meantime, you can be one of the first to try Zumly by joining our mailing list. You will receive betas and guides to play with it!