ZD Net: MSA is Microsoft's single sign-on service which authenticates users so they can log into their various Microsoft services. by Mary Jo Foley
'As happened two weeks ago, Skype Heartbeat site, has posted a message noting that users may be experiencing problems sending messages and signing in:
'"We are actively investigating problem, preventing users from signing-in and sending Skype-to-Skype messages! We'll let you know as soon, as issues are resolved."'