Twitter has launched a comprehensive security review after hackers hijacked the accounts of several high-profile users on Monday.

Analysts have expressed surprise that sites like Twitter, potentially hot targets for hackers and phishers, had long avoided such major attacks, and thus strong scrutiny by its corporate users. Since the hack of the site, analysts said they had been closely watching how Twitter and especially its corporate customers respond to the security breach.

"Certainly, with all the coverage Twitter has had about this, it will bring security to [Twitter's] attention," said Caroline Dangson, an analyst at IDC.

"It reminds us that we're dealing with a medium that is less secure and [that] we need to be more conscious of what we're putting out there and not take it for granted like we have," she added.

Twitter confirmed on Monday that hackers had broken into the accounts of more than 30 celebrities and organisations, including President-elect Barack Obama , Britney Spears , and the Fox News and CNN cable television networks.

The company said tools used by its support team were illegally accessed and used to send malicious messages, many of them offensive, to the compromised accounts.

The network was breached just two days after identity thieves launched a phishing campaign that tried to dupe users of the microblogging service into divulging their usernames and passwords. Twitter co-founder Biz Stone said he considers the compromise to be "a very serious breach of security."

In an interview, Stone added, "We're doing a full security review on all access points to Twitter." The first steps will be to "strengthen the security surrounding sign-in" and to further restrict access to the company's own support tools, he said.

Ken van Wyk, principal consultant at KRvW Associates, said that while individual users are unlikely to change microblogging habits due to the breach, corporate IT managers should move quickly to evaluate how such incidents could affect their firms.

"We're seeing [Twitter] used more and more for communications between managers and employees to keep everyone informed about what's going on," he said. "I suspect that a few of those folks might have a knee-jerk reaction to something like this and stop using it."

He added that the breach could inspire some IT organisations to develop applications that provide Twitter-like capabilities for in-house use.

Dangson agreed that companies should evaluate potential alternatives to Twitter or complementary, more secure tools to use with the service.

"We're not going to see a lot of people stop using [Twitter] because of this, but they might consider other forms of communication - more closed networks for certain information they're trying to share," she said. "I think people will be more cautious but they won't stop using Twitter."

Stone said that he expects that corporate users will see Twitter's "reaction and immediate behavior" following the breach as "a signal that we're serious about security and supporting commercial use."

As for home users, vanWyk said, "I don't' think people will say, 'Hey, now this place is corrupt.' I suspect [Twitter] will come away unscathed."

However, he added, "I think it would be good for companies to suffer a little bit when there's a major security breach. If they come through unscathed, where is the lesson? Where's the push to improve security?"