Twitter's 330 million users are being urged to change their passwords after some were exposed in plain text on its internal network.
Troy Hunt, who runs the Have I Been Pwned website, which logs breaches, said the error was not something that would worry him because there was no indication that the login passwords were seen outside the company.
Mr Hunt added: "We've certainly seen many precedents of simply flaws resulting in data breaches.
"The Red Cross Blood Service in Australia used an outsourcing provider who inadvertently published their entire database to a public web server resulting in Australia's largest ever data breach," he said.
All three experts urged users to act on Twitter's advice and change their password.
Mr Cluley said enabling two-factor authentication that adds another ID check to login attempts would help "harden" accounts.