Imagine you are 'alice' and want to send a PM to 'bob' and 'charlie'.
The normal way to do this would be:
/msg bob Hey, check out my new house!
/msg charlie Hey, check out my new house!
Using this mod makes it a lot easier: just write:
@bob,charlie Hey, check out my new house!
Bob and Charlie will then see something like
(alice) Hey, check out my new house!
Later, whenever you want to send a message to Bob and Charlie again, or whoever is the last person(s) you sent a message to, just use:
@ Isn't it cool?
Note: using a ':' instead of the space behind the receiver list will also work. However, you should not put spaces inside the player list.