press the T button when on a server with other players and type your message. all players will see it
Chat with our AI personalities
No. You cannot connect with other players with other versions.
Notch uses social spy to know what players of Minecraft are doing and how they use Minecraft. It will, for example, show if your playing from a browser or from the client and other minute details such as this.
you join
You press T to talk.
Yes, as well as animals, people/players and sometimes other objects if they glitch.