Hey mvkel, thanks for the great perspective. I totally agree that email is still easier for something like Fast Five.
We see WhereBerry as most useful for less mainstream things (Inside Job, Cambodian restaurant, Lebowski play) where you want to do it, but don't know who might want to join you. WhereBerry helps you gain some momentum, at which point you can organize it via email.
Did you see any of that kind of activity? I'd love to chat briefly if you want to get in touch at feedback@.