Does it work with Enigmail? (OpenPGP...)
For me, GPG is an integral part of working with email.
I've been using the alpha of Polymail for a few days now, it definitely exists/works and is actually pretty awesome.
How can it tell when my mail has been read?
Why do I need to "sign up for the beta"? Why do people think this is the cool trendy thing to do? Let us have it or let us know when it's finished. I don't need to know about it now.
Are they fishing for a buyer?