If Howard Dean (search) ends his presidential bid, his former campaign manager has a piece of advice: think twice about giving the Democratic Party the e-mail addresses of supporters.

Joe Trippi (search), credited with making the Internet a powerful tool for the former Vermont governor's White House effort, told a group of about 300 online mavens Monday that a decision of what to do with more than 600,000 e-mail addresses rests entirely with the Dean campaign. He was ousted from his job after Dean's third-place finish in New Hampshire.

Dean, if he were to drop out, would face the same question as Jesse Jackson, Ross Perot and Ralph Nader after their failed presidential bids: what to do with an enormous list of supporters, many of them dissatisfied with politics as usual.

Trippi suggested Dean might write supporters on behalf of the Democratic nominee to urge support, but he advised against turning over the e-mail addresses.

"I'm not sure I would turn it over to the nominee because I don't believe the nominee has a relationship with these people," Trippi told reporters at the O'Reilly Emerging Technology Conference. "The one thing about the Internet is having that relationship. I think the relationship is between Howard Dean and that individual."

Trippi said he isn't quitting politics, just taking a short break. He recently bought several Internet domain names under the moniker "Change for America" but is undecided what to do with them.

Trippi, who spent much of the last decade working in the Silicon Valley, credited the Internet for helping turn Dean from "absolute asterisk" to major presidential contender, singling out online forums for bringing together Dean supporters together in coffee shops and bars across the country.

He pinned the campaign's downturn largely on former Vice President Al Gore's endorsement, which, he said, sparked a torrent of media scrutiny and attacks from rival candidates.

The Internet isn't without its shortcomings as a campaign tool, Trippi said. Software needs to better verify identities, he said, noting that impersonators sent messages under the campaign's name, including one with derogatory comments about gays.

Communicating with supporters about campaign strategy posed another challenge. Many expected the campaign to share closely guarded secrets, such as the launch date of a major television ad campaign.

Also, too many campaign officials had voter e-mail addresses and bombarded them with messages, creating an unintended "spam" problem.