In my opinion, all private communication should be safe from eavesdroppers. For
one on one chats, many applications implement encryption through OTR or PGP.
I haven't found anything comparable for group chats, though.
I'm asking because I've made secure alternative to e-mail ResoMail, but I
don't see a large pool of users ready to switch to secure comunications.
For me it's a matter of convenience and network effects. Do I have to enter a
passphrase every time I send a message? Do I need yet another client for this
proprietary IM network? Does the client implement the features I expect? As for
your software, first of all, it's great that you're working on it. These are the
questions that come to my mind:
What are the benefits of ResoMail compared to email + PGP? You should explain
why it's necessary to break compatibility.
Can I trust it? People who really need cryptography will use software that they
know is reliable, e.g. a version of GnuPG that has been audited by an expert.
How do I know your implementation is secure? It's not enough to state that it's
open source.
You say it's open source, but where is the source code?
Is the traditional email client UX still the best way to go? Is it accepted by
users who grew up with Facebook and expect less friction?