ZDNet: Last week, users of Microsoft's Business Productivity Online Suite (BPOS) reported a service outage, and customers complained of more unplanned downtime yesterday. The problems affected Exchange Online, SharePoint Online, Communications Online, Live Meeting and the BPOS bundle of these services.
According to Microsoft, "Network performance is now back to normal, and the root cause is under investigation. We have updated our customers about this issue and apologize for any inconvenience this incident may have caused them."
Microsoft has planned some downtime for its BPOS services this weekend.