Right now according to National Association of Secretary of States the Democratic Primary/Caucus schedule looks like this:
http://www.nass.org/releases/2008%20Presidential%20Primaries%20Calendar.pdfJan 14th--Iowa
Jan 19th--Nevada
Jan 22nd--New Hampshire
Jan 29th--SC
Feb 5th--Alabama,Arizona,Arkansas,California,Colorado,Deleware,Florida,Georgia,Illinois,Kansas,
Michigan,Missouri,New Jersey,New Mexico,North Carolina,Oklahoma,Tennessee,Utah (and possibly Ohio,Montana, and North Dakota)
So, how does that affect the race?
Money and organization become paramount. Unlike previous years, a campaign won't be able to move their apparatus from state to state. You've got to be in 20 states on one day, that's alot more than having 3 or 4 teams skipping from state to state. The alternative is to focus on a region or group of states (ie Richardson the Mountain/Southwest/California, Edwards may ignore the Southwest and focus on Missouri/Michigan/Ohio/New Jersey as well as the South, Hillary and Obama everywhere, though even they may have to focus)
Pare it down some more and after NH, you've got to campaign in at least 20 states in 14 days. How does a campaign approach that?
The early races are vital for everyone, but especially those not named Hillary and Obama. However, since the primary season is so compact there's not much incentive for candidates to drop out before Feb 5th (what's an extra week more?), in fact it may be impossible to get off the ballot
Without the winnowing effect that primaries provide, it's plausible that candidates will be winning states with 25-30% of the vote on Feb 5th when a massive number of delegates will be chosen, and while the delegate selection rules are designed to prevent brokered conventions it certainly seems plausible that as many as four candidate could have large blocs of delegates after the voting is done on Feb 5th and by Feb 5th about 2/3rds of the non-superdelegates will be chosen (and I guarantee the Party doesn't want a brokered convention or the superdelegates having to make the choice)
It may shake out nothing like this, but the good old law of "unintended consequences" seems to have a higher than usual opportunity for havoc in this new primary set-up.