Off topic replies should be put in the "Off topic" forum, usually discussions turn into a completely different subject than the original making it hard to follow and useless. Besides this, there is something that is transparent to the users....the database size, this eats up disk space on the server, and as the number of useless replies grow, this space lessens, slowly but it does. So it is good to clean it a little from time to time, and especially the thread hollowcell is talking about, it is meant to show studio pics, and not to hold a 5-pages-discussion
