Hotmail imposes tracking cookies for logout
Hotmail users are now unable to log out of their account if the browser they are using does not accept third party cookies.
The move by Microsoft raises security concerns, particularly as PCs on corporate networks and in cybercafes and libraries are often set to reject cookies.
Third party cookies are most commonly used by advertising networks to track surfers across the web.
We've asked Microsoft what is behind its demand they are enabled, and whether it's considered the potential security implications.
http://www.theregister.co.uk/2009/11/12/hotmail_cookies/
Nope. You don't have to enable third-party cookies to solve that sign-out issue. See http://msmvps.com/blogs/donna/archive/2009/11/08/people-having-issue-to-sign-out-their-windows-live-id-or-hotmail.aspx