More than anything else, what I remember about the 2000 election was feeling as though Democrats and Republicans were basically giving us the same candidate. I was much less observant about politics then than I am now, but I talk to quite a few people who say they felt the same way. If those people are Democrats, they now feel really stupid. But life is about learning lessons, and it would seem that Iowans learned theirs.
In 2000, Republicans had 87,000 caucus voters and Democrats had 59,000. Eight years later when it has become very clear that you do not get the same thing no matter who you vote for, things have changed.
Republicans had 115,000 caucus voters. Democrats had 236,000. That tells me people now see a difference in what they'll get from candidates. And they are doing something about it.