The Internet was a critical factor in Barack Obama’s defeat of Hillary Clinton. But it could also jeopardize his chances against John McCain in the fall.

Obama has been called “the hottest start-up” in Silicon Valley and “the first real wiki-candidate.” His mastery of the Web – raising money, mobilizing voters, distributing videos – helps explain why he overcame Clinton’s enormous advantage in connections and credibility.

The Internet is value neutral, however. It delivers bad news as well as good news. It can unhinge Obama as well as unleash him. Any of his unguarded or inconsistent statements are immediately scrutinized, and carefully compared to every other statement he has ever made, neatly catalogued on YouTube.

More seriously, Obama has been plagued by a swirl of unfounded rumors – that he’s a Muslim and a foreigner, a radical and a racist. And his campaign admits that those rumors, fueled and fast-forwarded on the Internet, pose serious threats to his candidacy.

“We live in a different world than we lived in before,” Jim Margolis, Obama’s media adviser, told the Washington Post. “This campaign is only possible because of the Internet, because of the technology, because we could raise a couple of hundred million dollars (from) 1.5 million Americans. ... On the other hand, you’re constantly dealing with the misinformation that can spread quickly, where in 24 hours you can get millions of hits.”