Just ended yearly classical (turtle) tournament was with more than 2600 players! So swiss style pairing would help, however, the expectation is that the user stays for the whole tournament. That would be a difficult constraint for such a long running online tournament.
Knock out tournaments might work well since the winners would be likely to continue playing, though that too is not guaranteed.
Experimentation is required, like one suggestion above allowing swiss and knockout only for private tournaments. Based on how things go, they could be considered for official tournaments.
Knock out tournaments might work well since the winners would be likely to continue playing, though that too is not guaranteed.
Experimentation is required, like one suggestion above allowing swiss and knockout only for private tournaments. Based on how things go, they could be considered for official tournaments.