Forums are archaic in general, I won't say that they perform significantly better with other games. Modern games tend to have most or all the features (including communication) built into the game client, and with Toribash you're basically forced to go to forums to do even basic stuff like managing your inventory or selling items due to the lack of proper automated market. If not for that, forum would've probably died much earlier.

Its best days are long gone, you can see that even with Steam release in 2014 when we got the highest CCU numbers forum activity didn't change. I wouldn't even bother trying to attract players to forums that much now to be honest, other ways of keeping players in sound more promising if current trends are considered (proper matchmaking + ranking, SP/MP challenges, clans etc).