ourmedications said:

...Someone told me to send a message and receive a reply and to use that to find the sender's coordinates.  I do not see how this works.  Of course one can track clan members by using the clan roster.  It gives the coordinates of every clan member.  But what about nonaffiliated players?  How do you track them?

I myself have been tracked and found.  Today I got a one-to-one clan invitation and so I have the sender's in-game name, that's all.  I cannot figure out how to find his whereabouts.  He did not give his clan name, so I have no hope of finding out what clan he is in or what their setup looks like before replying.

Gyankyr

If you have name of the Clan you can find them in the "List of Clans"