In the days after the Boston Marathon bombings, the social media and entertainment site Reddit had the breakout moment it had been waiting for — but not the one it expected.

After site members, known as Redditors, turned into amateur sleuths and ended up wrongly identifying several people as possible suspects, Reddit went from a font of crowdsourced information to a purveyor of false accusations, to the subject of a reprimand by the president of the United States himself, to the center of another furious debate about the responsibilities of digital media.

Last Monday, Erik Martin, the site’s general manager, posted an apology, saying, “Activity on Reddit fueled online witch hunts and dangerous speculation which spiraled into very negative consequences for innocent parties. The Reddit staff and the millions of people on Reddit around the world deeply regret that this happened.”

In a subsequent interview, however, Mr. Martin was unclear about how it might play out differently in the future. “We could have reminded people about our rules on the disclosure of personal information; we could have shut down the subReddit earlier than the moderators shut it down,” he suggested. (SubReddit is a name for a subject forum where a thread or threads of conversation develop on the site.)