UPDATE #2: Microsoft has contacted users who voted in the Xbox Entertainment Awards to inform them of the "technical error" which resulted in personal data being exposed.
That information included users names, emails, Gamertags and birthdays.
All users who voted via the app have been awarded 1600 Microsoft Points (£13.60) in compensation.
The competition is now permanently closed.
The exposed details should not be enough to compromise a user's account, Microsoft reassured, before asking users to check that they had appropriate security in place for their account via Xbox.com/security.
The email is reproduced in full below:
UPDATE #1: Microsoft has issued a statement on yesterday's security breach, which exposed the Gamertags, email addresses and birthdays of thousands of Xbox Live users.
At no point were users' passwords vulnerable.
"Data security for all Xbox 360 owners is of the utmost importance to Microsoft," a company spokesperson explained in a statement passed to Eurogamer. "Upon learning on 19 March 2013 that a number of UK Xbox LIVE subscribers have inadvertently had a limited amount of personal data disclosed online because of an error with our Xbox Entertainment Award voting app, Microsoft took immediate steps to remove the Application from its UK Facebook page."
"We are working closely with affected Xbox Entertainment Awards voters who have been in touch with us to ensure that their Xbox Live accounts have not been compromised and will restore the Xbox Entertainment Award voting app to our Facebook page once the issue is resolved.
"Xbox Live customers who have any concerns should visit www.xbox.com/security for information on account security."
ORIGINAL STORY: Microsoft has hauled its Xbox Entertainment Awards website offline after user information was revealed.
MCV discovered what appears to be a security breach that resulted in the gamertags, email addresses and birthdays of some 2892 entrants made available to the public. Apparently those visiting the site could edit the information.
The website is now offline and Microsoft is investigating.
"We are currently experiencing technical difficulties with the Xbox Entertainment Awards landing page and have taken the site offline while we investigate," it said in a statement.
The Xbox Entertainment Awards was announced yesterday. It calls for votes in various categories, including games, TV and movies, and music. Everyone who votes is automatically in with a chance of winning an Xbox 360 Limited Edition Halo 4 320GB console, Kinect, Xbox Live Gold one year membership, 2000 Microsoft Points and other gubbins.
The plan is for the finalists in each category to be announced on 9th April, with interactive voting taking place on the Xbox Live dashboard until 16th April, and then the ultimate winners announced on 17th April.