There was a member not too long ago who got negged (or booted from a campaign) for post bursting if I recall correctly, but I can't remember his name for the life of me.  And the thing was, he wasn't a shitposter.  He was in a campaign, true, but when I looked at his post history most of his posts were pretty well thought out and constructive.  The only issue was that he made something like 150 posts per week and people were saying he was a spammer.

When I look at my unread topics list, often I see the same names pop up in the "last posted by" column, and usually those are the ones who are making rapid-fire posts with little thought to them, and that often happens in the altcoin section.

There are members who are essentially talented forum writers, ones who can write down their thoughts very quickly and lucidly--and they can probably type very fast as well.  As long as a post is constructive and on-topic, I don't see what the problem is.  From a campaign manager's standpoint, however, it's very much frowned upon to make multiple posts within the span of a few minutes--and in a lot of cases, it's against the rules of the campaign. 

I tend to think a lot of members are trying to make the max number of posts for their campaign and are either trying to beat the weekly deadline or get their "work" done as quickly as possible.  Usually the outcome is a bunch of shitposts, but not always.