* Alison Macrina:
I also think this is a really cool brainstorm and I agree with Isa and George about uniting Tor's products around common themes.
I also want to flag that the email part of Sukhbir's original idea is a really essential component. Email is used way more than chat. Popular email providers, like gmail, don't work very well in Tor Browser (they work just fine in Thunderbird). The filesharing extension would solve some of the needs people have with email, but not all. I don't know how to reconcile this, just acknowledging that it remains a problem.
That's a great point as well. So if we do go with chat in Tor Browser, we will still continue maintaining TorBirdy because other than what you mentioned about Gmail not being supported, Thunderbird offers support for add-ons like Enigmail which people prefer as compared to browser alternatives like Mailvelope.
So regardless of the decision we make, I think we will continue working on TorBirdy because the only alternative to that is using email in the browser :)