Newsweek does a cover story on the Edward's campaign for Iowa. (I have never seen any other cover story as hard to find on their website.)
I mentioned this for my Iowa predictions and preceded the Newsweek story which elaborates on the role of second choice candidates and the rural vote. Those crowded urban precincts don't get more delegates than the family that shows up in the lonely prairies.
Here is a more in-depth look at the Democratic caucus system, it is marred by a bad Richardson example. Richardson supporters after being told they are one short of a delegate would redistribute to other candidates. Having another candidate's caucus director realize they are one short and moving a supporter over to give Richardson a delegate to take it away from another candidate is a risky scenario given that they may be denying themselves that delegate after redistribution.