Now, Keybase is cool - particularly how it's effectively a key management system which drives a collaboration tool. We hoped originally they would provide it as a decentralised identity management system that we could hook into Matrix to replace our identity service. But in practice it seems to be centralised, and whilst the client is FOSS (https://github.com/keybase/client) the server isn't. So, it's more an E2EE-capable centralised collaboration tool built on a cool key management system. I believe their E2EE is based on shared keys rather than a cryptographic ratchet (Matrix uses inspired-by-Signal Double Ratchet with extensions), which is a simpler approach, but doesn't give you the option of PFS. I'm also not sure if their crypto has been audited (whereas we have a slightly ageing audit of Matrix's implementation over at https://matrix.org/blog/2016/11/21/matrixs-olm-end-to-end-en...).
[disclaimer: I'm project lead of Matrix and the author of the OP]
And with that any chances an easier way of having an ID/username? @<user>:matrix.org seems extremely easy and convenient for me but may not be the same for my friends and family without whom any messaging platform is useless.
PS. Totally rooting for you guys! I wish Signal was federated though.
Matrix emphasizes the use of third-party IDs (3PIDs) via dedicated identity servers. The idea is to link your Matrix ID (@user:server) to other identifiers like your email or phone number. Then you can use those to log in and other users can find you using them too.
What's the main difference with matrix? Is Keybase something you were aware of and decided against for some reason?