High enough that dumb threads don't make a 2nd page, yet low enough to make good threads have multiple pages... because dumb threads never make it past 3 pages
50 messages would lag constantly if the thread had multiple gifs. 40 might be all the website can handle!
What came first, the chicken or the egg? Obviously the egg came first if you are one of those that believe dinosaurs ever existed...
I tell ya sonny, I remember the days of 50 posts per page. We walked up hill to school both ways. Rivals crashes on national signing day were as true as the sun. Yep boy, the good ole days, back when men were men and sheep were nervous.