Is the party. Again.
In every single state that had a primary on Super Tuesday, Democratic turnout was up from 2004. The details are below the fold, and they're pretty cool to look at.
(Update 1: I've started to look at the Republican numbers. There are some things I'm seeing that they're probably not going to like. Details can be found at the bottom of the post.)
I got the 2000 and 2004 data from Dave Leip's Atlas of US Presidential Elections. The 2008 data comes from CNN's election page. Raw numbers of votes weren't available for the states that had caucuses yesterday, so I excluded those states. I wouldn't want to read too much into the exact sizes of the increases in each state, since there are a number of different factors that could have played a role in the increase. Viewed as a whole, though, this is very encouraging.
In 2000, the states above cast a total of about 7.7 million votes in the Democratic presidential primaries.
In 2004, the same states cast a total of about 8.6 million votes.
Yesterday, they cast a combined total of over 14.7 million votes.
That's huge, and it matches the trend seen in every single state so far.
Update - the Republican side:
On the Republican side, things don't look anywhere near as rosy. Bush ran unopposed in the 2004 primary, so it's hard to find numbers there, but the comparisons between 2000 and 2008 don't all look so nice.
In California, turnout in the Republican presidential primary dropped from 4,153,693 in 2000 to 2,248,461 yesterday. John McCain got almost 1.8 million votes there in 2000, and finished a distant second to Bush. He won yesterday, but came in well under the 1 million mark.
In Connecticut, Republican votes went from 180K in 2000 to 150K yesterday. In 2000, McCain received 87K votes, and barely edged out Bush. Yesterday, he received about 9,000 fewer votes, and won by almost 20 points.
In New York, the Republican vote count also dropped. In 2000, 334,126 votes gave McCain 43% of the total and a 2nd place finish. Yesterday, he dropped by over 20,000 votes, but came in first with 51% of the total.
The Bottom Line:
In the states where both Republicans and Democrats had primaries yesterday, a total of 127,346 more people cast Republican votes yesterday than in 2000. On the Democratic side, the number of votes cast went up by over 7.7 million. Most of that increase is since the 2004 primary season.