This applies to all kinds of RP's in general honestly, forum or no.

In D&D I had a DM who to put it most accurately let's power, control and authority get in his head. Using his power to simply make encounters unfairly tedious for players, railroad them into things, or even punish creative thinking at times because it could otherwise give the players an edge. Basically campaigns he did weren't lasting long and dying out because he taking the concept of "Players should listen to and be grateful to their DM" too far, forgetting that a DM is nothing with their players. If the players become disengaged, and they choose not to play it doesn't matter how much dominance or authority the DM tries to express, he's still just someone sitting there with a campaign, but without anyone to share it with.