[<channel>] [--user <name>] [<nick>]
Returns the last time <nick> was seen and what <nick> was last seen
doing. This includes any form of activity, instead of just PRIVMSGs.
If <nick> isn't specified, returns the last activity seen in
<channel>. If --user is specified, looks up name in the user database
and returns the last time user was active in <channel>. <channel> is
only necessary if the message isn't sent on the channel itself.