Macros allow you to read and use some game specific data, like your health, status of your connection, your mp3 player volume, console width and other info you can then use for example in your scripts.

There are two types of macros: protected and unprotected.
Protected macros can be used only to format you (team)messages. That means you can only use them in combination with say/say_team/echo/if and some other commands. Macros from that group contain some of your game status.
Unprotected macros can be used in combination with any command you like.

I have no knowledge of the $macros or other teamplay commands of ezQuake and their limitations.
As long as you cant create an auto-reporting config by binding all movement keys to a very complex "+left;$check_all_stuff_and_report"

It is already possible to create a very complex communication config that check conditions and report accordingly. Bps has developed a nice one for the qcon 2on2 and I made one for me and gt as well.