While Joe Mullin, the reporter who wrote the Ars Technica article, said there was no absolute proof that the user was Mr. Snowden, Mr. Snowden used the screen name TheTrueHOOHA on public Web forums where he posted photographs that clearly depicted him. In addition, the user’s reports from Switzerland between 2007 and 2009 appear to closely match the timing of Mr. Snowden’s service in Geneva as a C.I.A. technician under State Department cover.

“Snowden would soon move into a four-bedroom apartment covered by the agency. He’d blow off parking tickets, citing diplomatic immunity,” Ars Technica reported, summarizing many of the chats. “He’d travel the continent. He befriended an Estonian rock star (‘the funniest part is he’s a SUPER NERD’), raced motorcycles in Italy, took in the Muslim call to prayer from his Sarajevo hotel room, and formed opinions about the food and the women in Bosnia, in Romania, in Spain.”

While the #arsificial channel does not log and preserve such chats, the users had automatically recorded the chats on their own computers and volunteered to share them with the Web site, according to Mr. Mullin.

Mr. Mullin said that a number of longtime users of #arsificial sent in their chat logs, which from their formatting, time stamps and other technical details appeared to be authentic. In addition, he said, some of the logs were thousands of pages in length, and the material from TheTrueHOOHA was only a tiny fraction of that, scattered through material from other users, so it appeared highly unlikely that the material was fabricated. The other users asked to remain anonymous, and Ars Technica substituted “User” with a number for their actual screen names, Mr. Mullin said.

Mr. Snowden’s casual and profane, but apparently strongly felt, condemnation of leaks is an intriguing clue to his political evolution. He is now believed to be in a transit lounge at Moscow’s Sheremetyevo airport, hiding from American prosecutors who have charged him with espionage and theft of government property for leaking the N.S.A. material. Ecuadorean officials have provided him with refugee travel documents, since his United States passport has been revoked, and he has applied for asylum in Ecuador and other countries.