The messaging challenge Quip is going to have is that they have to call themselves a "modern word processor" so we have context to understand what it is.

But from the landing page this looks / feels drastically different from any word processing / document creation tool I've used in the past.

It might be interesting to test a variant that starts with a screenshot that centers visitors around what this has in common with today's word processor, and then hammers home the "awesome" part after that.