On Capitol Hill, Playing WikiPolitics

In Meehan's case, the edits were carried out by an intern who was updating the congressman's profile on his own Web site and altered the existing Wikipedia entry to mirror that, said Sandra Salstrom, a spokeswoman for Meehan. Among other things, the intern deleted an earlier campaign promise by Meehan to retire after four terms.

Wikipedia considers this "whitewashing," a benign edit compared with, say, "bad faith" and "vandal" edits.

Generally, clear violations are taken down within minutes, as was the case with recent commentary on President Bush. (Because of the frequency of attempted vandalism on Bush's site, it is no longer open to editing by new or anonymous Wikipedia users.) In one case, however, an erroneous entry suggesting that John Siegenthaler Sr., a former special assistant to Attorney General Robert F. Kennedy, had a role in the Kennedy assassinations went unnoticed for four months.

Kat Walsh of Herndon, a bassoonist and Wikipedia editor, said the site dissuades people from editing terms or profiles they feel personally invested in. But it happens, occasionally, and not just in politics: Some companies have tried to beautify their entries by entering press releases, she said.

Even Wales, the Wikipedia founder, has admitted repeatedly editing his own entry, a move he said he did openly but now regrets.

Standard operating procedure is to replace offensive alterations with the original text, and send a warning letter to the user of the Internet address that made the problematic change.

"You have not been blocked because you appear to have refrained from continued vandalism," a sample warning to Senate staffers reads. "We welcome contributions from all possible editors, including staff of the United States Congress. However, please comply with our policies, especially those pertaining to personal attacks and neutrality."

Neutrality can be a tricky or nuanced thing with political terms, which is why disputes are sometimes vetted by mediators and arbitration committees, also made up of volunteers, Wales said.

"Especially with politics, it gets more and more borderline on what's in bad faith or good faith," he said. "Reasonable people can find a way to work together. Unreasonable people get blocked, of course."