Does Acter collect any user data?

That is broad question and can not be answered "no" by anything that wants to consistently route information between participants. Additionally for every user we also have their open sessions and keep some security relevant information alive (like the IP when it last access it from) during the session for them to figure out if they have been compromised. We do not actively collect any of that information though nor do we keep it after use. Further more by not requiring a user to give us an email address or phone number they can stay pseudonymous to the degree that we can't even connect them to a real life person. You can find more information about metadata here.