Other secrets remain just that, usually because the politician in question has not been perceived as crossing an obvious line into hypocrisy, or he denies the rumors and no one can substantiate them. Perhaps no one wants to. They may not even be true.

“Most so-called open secrets are things we don’t really know the truth about,” said Alan Ehrenhalt, executive editor of Governing magazine. Regardless, he said: “It’s human nature not to pry into dark corners if you don’t have to. Most people would rather just let things be.”

And so it happens that a lot of states have lawmakers widely known for heavy drinking or sleeping with aides, whether or not the supposition is proved. One state official has long been rumored to be gay, and newspapers have investigated tips on his relationships. But only bloggers have published details, with little traction.

Rick Wilson, a Republican consultant based in Florida who has worked for Rudolph W. Giuliani, the former New York mayor, and Katherine Harris, the former Florida congresswoman, among others, said that most states have their own expressions for the circumstances under which open secrets stay secret. In Florida, he said, it’s the “Three County Rule” — no girlfriends within three counties of your home district. In New York, it’s the “Bear Mountain Compact” — nobody talks about what politicians do with their free time once they’ve crossed the Bear Mountain Bridge en route to Albany from points south.

“There’s a similar phrase in every state I’ve worked in,” Mr. Wilson said. “In a lot of cases it’s because the principals involved are powerful, and a lot of the people who know are aides or staff or lobbyists or even reporters who rely on these people for access. So you end up with this feeling of, ‘It’s just business, it’s not affecting their work.’ Once it starts affecting their work, then the rules change.”

Given the power of the Internet, though, the standards could now easily shift with each new salacious rumor reported online. One of the Internet’s main assets, its supporters say, is that it is unfiltered — but that allows sewage leaks of sorts, too.

Mr. Jarvis said bloggers constantly had to hone their judgment about when to ignore a rumor, write their own piece on it or — often the best choice, he said — link to another blog’s report on it.