From major conferences at the Moscone Center to small coffee shops in the Mission, San Franciscans are buzzing about Mayor Gavin Newsom and the stunning turn of fortune that in a few short days took him from being a candidate for governor to hiding out in Hawaii.

From Newsom's highs, like his law-breaking same-sex marriages in 2004, to his lows, like an admitted affair and alcohol problem in 2007, the telegenic, risk-prone mayor has always given his constituents something to wag their tongues about - and this bizarre chapter is no different.

Last Friday, hours after speaking before a bank of television cameras about the oil spill in the bay, Newsom announced he was dropping out of the governor's race and hasn't been seen at City Hall since. Word finally came Tuesday that he was on the Big Island with his wife, newborn daughter and in-laws. He left without telling his staff, who abruptly canceled a raft of major appearances on his behalf.

Newsom spokesman Nathan Ballard said Thursday afternoon that the mayor was preparing to fly back to San Francisco Thursday night and expected him to be at City Hall today. Previously, his staff had said they didn't know when he'd return.

It is unclear whether someone relayed the message to the mayor that his absence was being received at home about as well as a bright red sunburn. The mayor may have gone quiet - not even using his beloved Twitter in more than a week - but city residents sure haven't.

"I don't know why he disappeared," said John Hosford, 68, who was drinking coffee and doing a crossword puzzle at Javalencia in the Mission on Thursday morning. "He must be reeling from his gubernatorial shock, so I feel like he's taking a breather."

Jessie Churchill, a 35-year-old mom pushing twins in a stroller nearby, said she doesn't begrudge Newsom a vacation, but anybody else would have been in major trouble for vanishing from work with no heads-up.

"It's kind of typical - he seems to be a bit of a cad," she said in a thick British accent.

Political analysts are similarly divided over Newsom's vanishing act. Barbara O'Connor, a political science professor at Sacramento State University, said the gubernatorial dropout clearly wanted to avoid the media and decompress - but did it in a childish way.

"To not let his staff know is not civil. It's petulant," she said. "I can certainly understand wanting to get out of Dodge, but you do it gracefully, you say you need some personal space and then you go away. That's the way big people do it."

Corey Cook, a political science professor at the University of San Francisco, said the way Newsom behaves once he's back at City Hall will determine his mayoral legacy.

"He's clearly at a crossroads in terms of his career in public service, and he clearly has some decisions to make," Cook said. "If he comes back and says, 'Let's get to work on the city's business, and let's start solving some of these fiscal problems,' this will long be forgotten."

But organizers and attendees of Newsom's scheduled appearances this week may struggle to forget the mayoral brush-off. Privately, several of them are steaming that the mayor left them in the lurch.

His staff made last-minute cancellations on long-planned engagements including addressing 2,000 people at the Silver SPUR Awards Luncheon at Moscone Center on Monday, speaking to 6,000 at the Urban Land Institute conference Wednesday, meeting at his request with a dozen top business leaders to talk about jobs and appearing with his new police chief to tout a citywide reduction in crime.

City Hall folks have been buzzing about the missing mayor. "How does it feel to work for Mark Sanford?" one quipped to a member of Newsom's staff in reference to the South Carolina governor who disappeared recently and said he was hiking the Appalachian Trail but had really gone to Argentina to rendezvous with his lover.

Ballard said Newsom's explanation is much more mundane. "He was feeling under the weather, and he wanted to spend some time with his wife and child," he said. "As a human being, he's entitled to do that."

Ballard stressed that Newsom's "got a lot of work to do in City Hall," and one of his first priorities is meeting with the parties involved in the three-day hotel strike at Grand Hyatt Union Square.

Shauna Joseph, 55, was playing with her dog, Sophie, Thursday morning at a dog park near the mayor's new home in the upper Haight. She said Newsom must be exhausted from a grueling gubernatorial loss and a newborn keeping him up at night. "I bet he's stressed to the max," she said. "Maybe he's kind of feeling defeated."

While much about Newsom is unknown right now, that guess is probably a safe bet.