These days it's unthinkable to imagine a world without the internet.
The same goes with a larp without an IC forum.
In some larps the forum is used as a place where the players can have IC chats with their IC friends. But I'm seeing more larps using the IC forum as a place to undertake actions that can have big impact on the Larp itself.
I personally use the Manticore IC forum only to fill the gap between larps, but the actions taken on the forum are mostly without consequence on the Larp itself (unless the PC makes bold statements or such).
But now there are some larps that have e.g. a whole court action going on at their IC forum instead of having that whole scene on the larp itself. Personally I find that such a thing is becoming more a form of online-forum-rpg instead of a larp forum.
People who don't read the game forum (and there are plenty of those) can not follow that said court action and thus miss out on a part of the larp. In the end this can result in a lot of actions having happened in the larp world which only happened on the IC Forum. The result is that those who don't visit the IC forum may find the next larp event in a totally different setting.
Personally I find that a wrong direction, but what are your idea's on larp and IC forum, what is your opinion in how far one should be able to go on the IC forum? Let me know via the comments.