It is the race to be on the first page of the thread since it is often the only page that is being read. I'm not sure if the campaign participants today are being mandated to be on the first page of the thread but I'm not gonna be surprised and advertisers would like that.

I think OPs of a thread are to lock the thread whenever it reaches a certain number of pages. If anyone does have anything else to say, he can create another thread for his issue.