When MWLL is released, and (hopefully) league play starts up, this type of communication will become more important.
The Mechwarriorleages website has a fully functional battle system. It has challenges, date/time choices, a random map assignment feature, battlecoms where the two teams can leave messages for each other (not live, more like PMs), score reporting, score confirmation, score/game dispute feature, ranking in the ladder based on scores, and administration by ladder admin. The admin oversees map additions and deletions, match rescheduling, score/game disputes, and monitors the forum specific to that ladder.
This was before my time, but apparently VL had some sort of web lobby that served an equivalent service, although not as structured.
