To the above discussion I'd like to add this insightful early analysis on the turnout and the impact of convenience voting on the election (I recommend reading the article but also clicking through to the linked-to-report, which looks big but is mostly the numeric data after you get past the first half-dozen pages).
http://www.minnpost.com/ericblack/2008/11/07/4454/the_big_jump_in_turnout_that_wasnt
]]>