Seems quite a marketing lie, zero knowledge, while you really want _all_ the knowledge about all my sensors, and the way I use your product. While I get no knowledge of how your servers work and what you do with it.
We're familiar with the concept from previous work, but decided it wasn't worth creating an MVP with it.
One can architect a service to be zero knowledge like the terrific job http://www.tarsnap.com/ does. Unfortunately it's pretty hard for us to do when the core value proposition of our product is that we connect your hardware to other APIs (Dropbox, Facebook, Twitter etc) (which don't follow a zero knowledge architecture).
Cheers,
Marcus