Trolls cause more problems than they solve. At most, they can make a local forum look slightly more appealing, but that's nothing compared to the problems they cause. Their roots can cause damage to the foundations of any sensible thread, not to mention the lowering of spirits which leads to reading hazards. Furthermore, trolls rest on threads and drop their mess on unsuspecting members. And also, there is the cost of hot air.

Not worth the hassle in my opinion