Iowa & first-time voters & the youth vote: If the vote had been solely among previous caucus attendees, Edwards would have won with 30% of the vote.

From The Wall Street Journal:

Pollsters found that Mr. Obama handily beat his competitors by grabbing more first-time voters and more of the youth vote. According to the polling, if the vote had been solely among previous caucus attendees, the outcome would have been much different: Former Sen. John Edwards would have won with 30% of the vote, and Mrs. Clinton and Mr. Obama would have essentially tied for second.