At Catapult we utilize Office 365 and ADFS for some users.  We also have set up a SharePoint Online site for all of our SharePoint consultants to use for testing and demo purposes.  Well today it came to out internal IT department’s attention that the SharePoint consultants could not access their sites.  An error occurred when attempting to login.  Joe Stocker, Catapult’s IT Manager, wrote a great blog about the ADFS Token Signing certificate and the need to update it each year.  If you are running Office 365 with ADFS I highly recommend you read his post, http://blogs.catapultsystems.com/IT/archive/2012/03/07/cannot-sign-on-to-office-365.aspx

Good information to know and prepare for with a move to the cloud!