Ahh I have to think now.
Back from SFC 1 to SFC OP we had hundreds of people online in MPlayer (the precursor to GameSpy) and on into GameSpy.
Over the years we did have groups we called 'Fleets' (Star Trek Clans!) that would compete. There were so so many back then! The device used to host the competitions changes over the years, including one called StarLance (I think I have that right), GZ Leagues, and another more recent one (forgot the name) that kept the trend going before as SFC OP hit the final days of online competitive play.
If you play online in GSA today, you may find people still wear their tags, even though they have no practical meaning today besides listing a personal history with the game. There were many Fleets that lasted all the way from SFC 1 through to SFC OP.
During that time though, there was always a group of poeple who generally stuck to the Dynaverse gameplay. There the competition was on the map, and was not only fights in mission, but over control of resources. AFAIK, those guys were not as as Fleet per say, although they might affiliate with one. They generally enjoyed picking a race on the map and fighting for their side. I don't know as much about the Dyna side, as at that time I was more into the GSA than the Dynaverse.
As for future plans: AFAIK, the Dynaverse Association was never interested to host rounds for competitive play. Even when GZLeagues was here, and its later replacement, those services hosted all matches. The DGA (Dynaverse Gaming Association, this site) never hosted them. So that is to say, if things pick up enough, and if DGA remains the same, the DGA would likely not take the lead in what Starlance or any of those services did, it would be up to some other people to create a new service for hosting competitive play again.
If things picked up to that degree again, it would be very exciting.