If there are particular topics people want covered then stick up a post in the OT section. If it is interesting / popular it'll be well used and appear in the 'view unread inc OT' list every time you log in.
I'm not against a healthy OT section, I have used it for all sorts of stuff myself, Sandwiches, Pets IT help - you name it! This IS a car forum though so the focus should be on the cars.
As we say, if the OT topics are good and have a healthy response then they can be stickied.