Earlier this month, volunteers for Republican presidential candidate Ron Paul, aided by an extraordinary outpouring of grassroots Internet support, made U.S. electoral history by raising more than $4.2 million in one 24-hour period. “The Web Takes Ron Paul for a Ride,” noted The New York Times.

Four years ago, the likes of Howard Dean and John Kerry looked for a lift online from website donors, e-mail updates, high-profile blogs and political gatherings via Meetup.com. We’re now watching campaign 2.0, where 20-plus presidential candidates may disagree on Iraq, health care and taxes, but their actions speak as one about the need to add Web 2.0 tools to their communications, fund-raising and outreach strategies.

With less than two months to go before the primary season begins with the Iowa caucuses on Jan. 3, candidates are sprinting for donor dollars, media coverage and votes. And they are targeting online communities, social networking sites, YouTube channels, audio clips, Flickr photo feeds, sponsored blogs, self-contained content widgets for supporters’ websites and more to connect with all of those constituencies. Democrats John Edwards and Hillary Clinton used website videos to announced their candidacies.

Businesses can take a page from the candidates’ social networking frenzy. Web 2.0 applications make it possible to promote a corporate image while creating an opportunity to become more accessible and responsive to customers through new communications channels. But beware: There’s an authenticity trap here. Experts say it’s difficult to pursue so many new channels without diluting your message, without seeming as if you’re trying to be everything to everybody.

The Ubiquitous Campaign 2.0

The candidates are everywhere you look if you spend time online. Some examples:

On the hustings in online communities. On eons.com, an online community for retiring baby boomers, Hillary Clinton has been given blogger and storyteller badges for posting frequently and sharing her life story. On Democrat Barack Obama’s personal homepage on BlackPlanet.com you can watch his recent talk show appearances on the Tavis Smiley Show and The Tonight Show to your heart’s content. His page on the Latino community MiGente has a link to Obama TV en espagnol.

Full YouTube ahead. All the major candidates have their own YouTube channel (and MySpace and Facebook pages). In addition, a video project called 10Questions presents voter questions to the candidates, who then post their video answers. As of Nov. 21, Republican Mike Huckabee had uploaded nine responses addressing Internet neutrality, whether the United States is a theocracy and whether marijuana should be legal. (Obama was the only other candidate to post any responses.)