You can contact me via XMPP, which is a simple, federated IM protocol like email, or via Session, a decentralized and private (albeit limited) messenger.
XMPP: firstname.lastname@example.org (preferred)
I’m not particularly active on Session, so XMPP is highly preferred unless you have a really good reason to use Session.
Why not Matrix?
After hosting and using XMPP and Matrix, I much prefer XMPP. XMPP is more mature, meaning it has many choices for server and client software. Matrix is relatively new, so the only server with 100% spec compliance is matrix-synapse, a horrible bloated piece of crap that no one should try to host. You can use dendrite or conduit, but those aren’t fully complete. I don’t like any of the popular Matrix clients either. On top of that, Matrix rooms leak your full Matrix address to every participant, while XMPP rooms let you set a nickname and won’t leak your homeserver or real username. Also, XMPP users are pretty evenly spread across many homeservers, while Matrix users overwhelmingly choose Matrix.org as their homeserver.
You can also find me in this site’s XMPP room. This room is totally dead at this point, but I’m keeping it there in case this site shoots up in popularity or something like that.