That is one thing you really don’t want guests to your forum to think, yet I see plenty of forums online that don’t really let you know what they are about on their index. With some sites its obvious with their URL or title, others use graphics or text on the forum index to let you know what their forum is about, but some don’t seem to take guests into consideration.
I’ve run into many forums where I can’t really figure out what they are about, and this is not a good thing. It’s not hard to add a quick “About us” or something along those lines. It’s also going to hurt you with Search Engines, because if people can’t decipher what your site is about, how is a bot going to do that? I’d suggest adding something in your title to make sure you are portraying yourself correctly to visitors to your forum. I’d also recommend a welcome message on your forums for guests that displays and explains what you’re about and why these people should register with you.