The cards are on the table. The challengers to Mayor Thomas Menino, namely Councillors Sam Yoon, Michael Flaherty, and activist Kevin McCrea, have played their first hands.

And almost overnight, the talk around the proverbial City Hall water cooler has turned from tones of 'They don't have a chance against an incumbent,' to a subtler 'This is going to be interesting.'

The city is on the cusp of change, say more than a few astute political minds, no matter who wins. That change could be one of voterdemographics, political campaign strategy or possibly even the fundamental way Boston works.

"I'm obviously not a politician," said Yoon in an interview Tuesday. "My approach to solving problems doesn't begin and end with politics - that's the fundamental change. The way we approach our schools, our youth violence, our basic city services, it's almost exclusively driven by politics in this town. And that frankly is due to the system that allows the mayor's office to have control over the debate, the agenda and the city council. It came to the fore a century ago, designed by Yankee Republicans at the State House who were afraid of Irish rule. Every mayor since then has been a mayor in that system, and that does not work anymore.

"We all realize that there are good ideas from hard-working people, people who care so much about their city. They need to be empowered by city government and not controlled by city government."

Yoon and Flaherty have both stressed an inclusive campaign of change, using websites and e-mails to solicit ideas from voters. Flaherty has been the first to hit a few bumps on that road. The first came when Kevin McCrea - a man who once named Flaherty in a successful lawsuit against the City Council for violations of the Open Meeting Law - joined the race for mayor. And, last week brought revelations that Flaherty may have tried to pull strings at the Police Academy for his wife Laurene.

Menino, according to some who are privy to closed-door strategy sessions, will take another tack. Instead of appearing on YouTube, the mayor will appear on your doorstep.

"He's got 16 years of pros and cons and he's not hiding from anybody," said a former Menino staffer. "Who he is is somebody who interacts with people."

Following the tried and true path, Menino has hired Cence Cincotti Strategies, a relatively new firm whose principals have deep roots in local politics. In the past, together or separately, Dan Cence and Jay Cincotti have helped out gubernatorial candidate Chris Gabrieli, District Attorney Dan Conley, City Councillor at-Large Steve Murphy and Allston-Brighton's state Rep. Michael Moran.

Thus far, the election seems to be shaping into a battle between the bulwarks of old school Boston-style political campaigning, using ward leaders, neighborhood activists, and key constituent networks, versus the new champions of technology-driven "grassroots" campaigns.

"Michael Flaherty and Sam Yoon are trying to do the Barack Obama thing and Menino is going to stick with the old style of political campaigning in Boston," speculated Catherine O'Neill, a longtime Dorchester political hand who is still considering a run for council at-Large. "But I think the battle is going to be won in the middle. This mayoral election will set the standard for new campaigns in the city of Boston. People will adjust to how much the new style works and how much of the old style is still effective."

Where that line falls could depend, at least in part, on the magnitude of the "Obama effect."

Over 232,000 people voted in the city in President Barack Obama's election, a 14 percent rise over 2004, according to MassVote. Municipal elections traditionally have much lower turnout. Around 91,000 voted in 2005's mayoral contest. But thousands of first-time voters were registered last year, mitigating one barrier that any Get Out The Vote crew often faces. And many of those new eligible voters were progressives and people of color.

"I think there are a lot more new voters out there than there were before the presidential election," said John Barros, who took a few months off as director of the Dudley Square Neighborhood Initiative to coordinate half of Boston for the Obama campaign. "In many ways this would be the first time that those new voters will be thinking about a local election, and there's a lot to think about."

Barros added that he thought many of the new volunteers he organized to haul doorknockers to New Hampshire and set up phone banks would definitely return.

"The question is really where these people's loyalties will lie, but I think they will be at work in this election," he said.

Menino, it should be noted, supported Obama rival Hillary Clinton in the primary last year. Clinton ended up losing Boston.

In past elections, Menino's team has been able to count on his popularity in communities of color. When he could count on over 80 percent of the votes in a given neighborhood, campaign stickers, signs and pamphlets weren't needed. Just a van on Election Day would suffice.

That might not work this time around.

Yet another factor is the unprecedented fact that two at-Large seats are open on the City Council. A higher turnout of any kind often benefits the challenger, says the common wisdom. And particularly if more people of color and/or women join the council race, more voter interest would be drummed up.

Felix G. Arroyo is a strong favorite in the current field of at-Large candidates and former Michael Flaherty-staffer Andrew Kenneally might be considered a good possibility for the second slot as it stands. Jean-Claude Sanon, Doug Bennett, and Marty Hogan round out the field of those who have already announced. Roxbury's Bob Terrel ended his campaign Wednesday.

Who the next round of candidates will be is still a big unknown, because many of the possible candidates named by bloggers and reporters like so many pinballs in print have already opted out. The full field won't be fully known until May, when deadlines for pulling papers arrive.

Tomas Gonzalez, though he hasn't said it outright, is said by those who know him to be out of the running, as is April Taylor. Both didn't return calls for comment this week.

And Yoon staffer David Halbert said he has other fish to fry.

"I've been thinking about it, and a lot of people have encouraged me," said Halbert in a rare on-the-record interview Tuesday. "But I'm not going to throw my hat into the ring. I'm going to be getting involved in Sam Yoon's campaign for mayor, it's too important right now."

Dorchester's Nurys Camargo, another rumored runner, took a policy job at Mass Bay Community College in December, lessening the chance of her bid, though she still said this week that, "anything can happen."

That leaves Sen. John Kerry's political director Ayanna Pressley and Catherine O'Neill. Well-placed sources have said Pressley isn't running, though Pressley herself leaves the question open. O'Neill said her decision is some ways off, but added that she is screening her calls this week due an influx of supporters urging her to run.

Much has also been made of Menino's lack of an announcement. Many recall Mayor Kevin White's shenanigans in the spring of 1983, when a well-placed leak caused the Boston Herald to announce "White Will Run" in a front-page headline on the very day White announced to the world he would not run.

But one observer close to his stealth-campaign - which is holding strategy meetings, fundraising and hiring consultants - said a decision to wait as long as possible to announce would make perfect sense if Menino does intend to run.

"Once you [announce], everything is looked at through a political lens," he said. "If he goes on a talk show, does that trigger equal time? It would put a time constraint on an incumbent that still has enormous amount of continuing duties."