That's why usually a smaller forum is much more enticing than a larger forum, because they aren't targets for bullsh*t.
Yeah, but every community/forum that starts out small aspires to grow and once you start growing, certain restrictions have to be put in place to ensure that things don't spiral out of control.
Being able to PM multiple members is only an additional feature and not a necessity. Maybe, in the near future, we can work something out to allow trusted people (like those in official groups) to send out invites for PM convos. Nothing's confirmed though so don't quote me on it.
I quoted you
In my small amount of experience I gained in developing a forum for my crew (don't worry, I'm not trying to steal GTAF), I've learned that every option, whether it be a host site like ProBoards, or software like IPB, has different things that make them, well, different. Proboards required little effort and was relatively easy to maintain. It also had the ability for the host of a private conversation to add new members to the conversation as they pleased. We used this to our advantage to keep things out of public eye (back then we were hiding a lot of private GTA stuff), so that way all who were trusted could converse freely in the privacy of a PM. I don't know if IPB has an option like that, as I haven't researched it enough, but as of right now we are enjoying our little shoutbox :3