NEWARK, N.J. -- Newark Mayor Cory Booker and San Francisco Mayor Gavin Newsom are blazing a new trail in political discourse from opposite sides of the country as they build huge Internet followings on Twitter's fast-growing social network.

They don't lead the biggest U.S. cities -- San Francisco ranks 13th and Newark 64th -- but have gained prominence by replacing heavily vetted, sterile political prose with personal missives on the stream of consciousness confessional. So much so, that they now have more followers on Twitter than all other mayors, all 435 members of the House of Representatives, 99 of 100 U.S. senators, and 49 of the 50 state governors -- among users carrying the "political" tag on the Twitterholic tabulation site.

Click here to read Mayor Newsom's Twitter

Online social networks are rapidly making traditional political advertisements obsolete, said veteran political strategist Joe Trippi, who used Internet fundraising to propel Howard Dean's 2004 presidential campaign. The social networks are giving elected leaders like Booker and Newsom a new way to satiate the public's hunger for transparency.

"These are the first politicians to build considerable followings on Twitter, and they're doing it by taking the filter out and showing people who they really are," Trippi said of Booker and Newsom. "Twitter and these other social networks and new media demand authenticity. This is the future."

Click here to read Mayor Booker's Twitter

As recently as May 9, Booker had 3,909 followers. That number soared after he took over the postings -- called "tweets" -- and replaced his staff's staid announcements about upcoming appearances and fundraisers with a flood of personal reflections and misgivings.

Tweets like the one below helped the 40-year-old Harvard graduate, who is trying to transform Newark from an icon for urban decay into a prosperous city, boost his following to 125,063 by June 4.

"So frustrating 2hear, 'this is how we've always done it,"' Booker tweeted May 17. "I support free speech but I

m seriously considering banning those words from CityHall."

The Twitter format, which limits messages to 140 characters, seems tailor made for Booker and Newsom -- both witty, charismatic leaders on the rise. Newsom, 41, has amassed 492,838 followers, most of them since March. Twitter Inc. is headquartered in San Francisco.

"Visiting truant kids at their homes -- surprise visits -- with Balboa H.S. Principal Gray," Newsom tweeted March 12. "if your one of them.... Listen to the knock:)."

As of Saturday, Newsom ranks ninth on Twitter among all elected officials carrying the "political" tag, according to Twitterholic. Booker is 13th.

Who's ahead of them?

President Barack Obama and former Vice President Al Gore rank first and second respectively. Sen. John McCain is fifth and California Gov. Arnold Schwarzenegger ranks 10th. Others in the top 12 are mostly media organizations and political commentators.

California Attorney General Jerry Brown also enjoys a sizable Twitter following, although he doesn't carry the political tag. Brown, 71, posted his mother's banana cake recipe a few months ago to his page on Facebook, another online social network.

Biz Stone, who co-founded Twitter, said politicians are increasingly establishing themselves on social networking sites, much as entertainers have done.

Newsom ranks 101st among all Twitter users, just a few spots behind singer Mariah Carey (95th). He used Twitter, Facebook and YouTube, the popular video sharing Web site, to announce in April that he would seek the California governor's office.

Booker ranks 247th among all users and is closing in on celebrity Paris Hilton (237th.

Stone sees Booker and Newsom's emphasis on personal transparency as a triumph of humanity, rather than technology.

"If they have good character and compelling things to say they'll make friends," Stone, who is fan of both men, said of Twitter politicians.

Robert Thompson, a professor of television and pop culture at Syracuse University, said the transformation in political communication being fostered by social networking is as profound as the one created by the "fireside chats" President Franklin Roosevelt introduced via radio before World War II.

"Twitter is the biggest thing in politics since the invention of babies to be kissed," Thompson said.

Booker compared the level of personal connection to sitting down simultaneously with thousands of people at their kitchen tables. He's tweets about his penchant for coffee and working late and has a proclivity for quoting renown philosophers and leaders.

"I don't have to go through the media to reach people anymore," said Booker, who estimates that he's gaining 5,000 to 7,000 new followers on Twitter every day. "My staff has been concerned, but I've seen how it lets people connect with me."