Microsoft admits to Hotmail privacy flaw

Microsoft has been forced to completely redesign the technology behind its Hotmail free email service after a privacy flaw came to light.

It will be next month before the flaw - which sends user email addresses to banner advertisers - will be rectified, said a Microsoft spokeswoman. She added that the service, which is used by 67 million people worldwide, will not be affected during the redesign.

The flaw allows some email addresses to be sent to third parties because of an HTML quirk. Microsoft claims there is no evidence that the advertisers are using the email address information.

When an HTML page contain an advert is accessed, the web address and user's login name is sent to the advertiser. Microsoft said it has taken the best part of three months to redesign the email service so that the flaw doesn't happen in the future.

Although Steve Ballmer, Microsoft chief executive, recently acknowledged that Hotmail was successful at generating advertising revenues, the email service has been plagued with problems. In June Microsoft received complaints that some users had lost their address books and saved mail while others claimed they had received spam emails.

Also in June some members received messages, allegedly from the company, which threatened to cancel their accounts. Those message turned out to be pranks.