The talk function may allow you to "talk" to your friends or associates
who have internet connections and who are logged on at the same time you
are. If you know someone is logged on at the other address
(zack@magic.nowhere for example), then to talk to them you would type: 

ux1> talk zack@magic.nowhere

They would then get a message flashing on the screen saying you (your
email address) wanted to talk to them and it would tell them what to type.
Once the two of you are connected, you are given a split screen, in which
you get one half to type in and your friend gets the other. To get out of
a talk session, you type: 

 [control] c

(Which means you hold down the control key and then hit the C key.) The
one downside to this function is that not all places have it because it
does use up a lot of resources.