The Obama campaign's message perfectly suits the motivation of the kind of person who puts money behind a candidate: the desire to be part of history—a claim Clinton could have made as well, but rejected in favor of the "inevitability" approach. How many people are inspired to donate to the inevitable?

Political Junkies.

Once, political aficionados were too few for their votes to have noticeable impact, and surveys showed voters rarely based their choices on strategic considerations. But their ranks have risen ever since Theodore White's 1961 book The Making of the President, 1960 invented the mass market for political strategy.

This year, that audience is expanding thanks to a plethora of inside-baseball politics programs on three cable news networks and a growing stream of political websites. (They're still a microconstituency: the peak audience for a top political chat show is well below two million.)

Political views aside, these aficionados share an obsession with the rules of the game, the ups and downs of the daily news cycle, and process and story-line rather than policies. This year, it seemed that every undecided Iowan interviewed at a rally was second-guessing the candidates' strategies or weighing their "electability."

Dedicated political hobbyists could easily tip the scales in a state where, even in this record year, Democratic caucus turnout was just 250,000. Relatively upscale and educated, they can indulge their political passion by volunteering, attending rallies, donating, and, of course, voting.

Obama's history-making quest proved far more appealing to political junkies than Hillary's theme of the steady workhorse. Politicos love an exciting contest, and hate "inevitability"—and may now rally to Clinton only after it appears some are trying to force her from the race.

Entry-Level Pundits.

The steady increase in programming hours, columns, and websites devoted to political strategy fuels an ever-growing demand for analysts and bloggers who can explain the election.

Many local newspapers now have their own political blogs, while TV and talk radio need ever more guests with some pretence to political expertise. Even amateurs can get into the act, by commenting on blogs (or clawing their way into a Frank Luntz focus group).

But, rather than making political analysis more diverse, the relative inexperience of the expanded punditocracy, and their exuberance for the "horse race," produces more pack journalism. The conventional wisdom becomes more entrenched, skewing the information that flows to voters.