The first and second page gets all the attention. It also contains sometimes the best brains and best contributions. A spammer would always avoid the first and second thread pages because he can be easily dictated. The first two pages also attracts the highest merits.
Whilsts that might be true in some topics, it cannot be generalized as it all depends on the topic/subject that is being discussed, as well as the users that are participating in the said discussion, there are threads that garners attention right from the first page to the last, and by last i mean down to the fourth page and even more. Mind you too that the best brain/contributor to a topic can make their first post on it in the 3rd or 4th page or even more, like i said in my earlier response in this thread, how much time you have to yourself per day in RL determines how quick you respond to a topic, the most knowledgeable person about a particular subject might be busy in RL when that topic is posted, and when they are less busy to join in the conversation, it has already gone past the 2nd page, and despite that, their reply remains a constructive and quality one.
Having said that, mind you that spammers still make posts in the first pages of new topics, they don't care what you think about them, they just say whatsoever they want and move on; you might be correct in the aspect of merits because only few people read a thread above the second page or so, but again there are exceptions based on the subject that is being discussed and how the discussion progresses.
