The American firm was ordered to hand over the information by a court in California after a successful legal bit by a UK local authority.
It follows a failed bid by Manchester United player Ryan Giggs to force the company to hand over the identities of the first tweeters to reveal he was the footballer subject to a super injunction over an extramarital affair.
The latest legal bid for information from Twitter succeeded because South Tyneside took the legal fight to the Superior Court of California, rather than pursue the action as Giggs did, through the British court system - which has no jurisdiction over the American firm.
San Francisco-based Twitter has now handed over the name, e-mail address and telephone number of South Tyneside councillor Ahmed Khan.
Mr Khan was accused of being the author of Twitter accounts that criticised the council and other councillors. Mr Khan described the council's move as "Orwellian", after Twitter e-mailed him earlier this month to say it had handed over his details.
However, he denies being the author of the material the council believes to be defamatory.
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He said: "It is like something out of 1984. If a council can take this kind of action against one of its own councillors simply because they don't like what I say, what hope is there for freedom of speech or privacy?"
Mr Khan said the information Twitter handed over was "just a great long list of numbers".
The Californian subpoena ordered Twitter to hand over 30 pieces of information relating to several Twitter accounts, including @fatcouncillor and @ahmedkhan01.
Mr Khan added: "I don't fully understand it, but it all relates to my Twitter account. It not only breaches my human rights, but it potentially breaches the human rights of anyone who has ever sent me a message on Twitter.
"A number of whistleblowers have sent me private messages, exposing any wrongdoing in the council, and the authority knows this."
He added: "I was never even told they were taking this case to court in California.
"The first I heard was when Twitter contacted me. I had just 14 days to defend the case and I was expected to fly 6,000 miles and hire my own lawyer - all at my expense.
"Even if they unmask this blogger, what does the council hope to achieve? The person or persons concerned is simply likely to declare bankruptcy and the council won't recover any money it has spent."A spokesman for South Tyneside Council said the legal action was brought by the authority's previous chief executive, but has "continued with the full support" of the current head.
He added: "The council has a duty of care to protect its employees and as this blog contains damaging claims about council officers, legal action is being taken to identify those responsible."
Twitter was not available to comment on the case.
It is believed to be the first time Twitter has bowed to legal pressure to identify anonymous users and comes amid a huge row over privacy and free speech online.
Footballer Ryan Giggs attempted in a failed bit to force the firm to hand over information in the High Court in London this month.
The successful move to use California courts is likely to be seen as a landmark moment in the internet privacy battle.
The council launched its case in an attempt to unmask an anonymous whistle-blower who calls himself Mr Monkey.
The action is believed to have cost council tax-payers hundreds of thousands of pounds.
The unprecedented ruling has prompted a row over freedom of speech, with experts warning that it may lead to a flood of actions by lawyers in other cases seeking to obtain personal information about people who breach super-injunctions or post libellous messages on Twitter.
Tony Wang, its head of European operations, warned last week that it would not seek to protect users' confidential information when legally required to hand it over.
He said the most the company could do was to inform users before it released their details, to give them a chance to challenge the rulings in court.
Amber Melville-Brown, a media law specialist counsel at law firm Withers LLP, said: "This case concerning serious allegations about South Tyneside councillors could have significant repercussions across the blogosphere.
"With Twitter quietly assisting in the process, the case could have an equally significant impact on future applications by those seeking to protect their privacy and reputation anywhere in the world."
Mark Stephens, a leading media lawyer who has represented Wikileaks founder Julian Assange after the US government sought to obtain his Twitter account details, said: "I think it is inappropriate for a local authority to spend money on this kind of exercise."Local authorities cannot sue for libel and if individual councillors have been defamed, they should take proceedings at their own cost."
Since 2008 Mr Monkey's allegations against councillors have ranged from ballot-rigging, drug-taking and fiddling expenses, to a claim that one ordered a public bus to turn around and pick him up from a pub late at night. The last post on the blog in 2009 says there will be no more postings.
The legal action to unmask the tweeter and blogger was brought by three councillors and a senior official: Ian Malcolm, the council's Labour leader, David Potts, former Conservative group leader who is now an independent, Anne Walsh, a Labour councillor, and Rick O'Farrell, head of enterprise and regeneration.
Mr Potts said not only had he been a victim of the blog, other politicians across the party spectrum, regional leaders and council officers were as well. He said the false things said about him had an impact on his family.
Media lawyer Steve Kuncewicz said he thought the council's case was significant as a "point of principle", but doubted it would have much impact on the legal bid by Giggs to get Twitter to release details.