[larrys]

"which is that some people are all too aware that they get NIL karma from a submission unless they are the very first to submit that link"

As a side note to this if you submit a link that has already been submitted you bump up the karma on that by one point. So even if you submit a link first (by the method you describe) and it doesn't make it to the front page or get "organic" upvotes the mere fact that someone else has the same idea, but was a minute late, gives you an extra karma point.

Added: So the conclusion is that if you are trying to get karma it pays to spend time adding the obvious suspects rather than the outliers (say a story from the NYT or Techcrunch that others will do the same.)