I agree, and I see a big market especially in academic publishing. A lot of course book text is written in a collaborative fashion with word docs emailed back

I agree, and I see a big market especially in academic publishing. A lot of course book text is written in a collaborative fashion with word docs emailed back and forth. Penflip could be to collaborative writing what Dropbox is to team file sharing. Being a single cofounder might have been a negative factor, in your rejection.