As mikeywith cleverly picked up here, some of these spammers seem to write a bunch of posts in advance, save them as drafts, and then just release them all during the next "quota period", which is why they can spam so many posts so quickly. I would add the Stake campaign to the YoBit campaign as being guilty of this behavior.

We need bans. Bans for spammers and bans for managers who enable the spammers. There are some users I've reported 50+ times in the space of a day or two, all their posts are trashed, and then they are back the very next day, posting twice as much to make up for the all their deleted posts. There is a stickied thread in Services saying these users will receive bans for this behavior - this kind of spamming will continue indefinitely until this is enforced.