Revoking a Users Sessions from SharePoint Online
A new PowerShell Cmdlet was released with the latest version of the SharePoint Online Management Shell named Revoke-SPOUserSession, this is really cool as it allows you to revoke all sessions that a user has open to SharePoint Online, which could be great if a users device is lost or stolen OR you fancy playing a practical joke on a co-worker who is giving an important demo of SharePoint Online :)
The Cmdlet is super-simple to use and below is an example of it in action, after connecting to the tenant as a Global Admin you simply execute the Revoke-SPOUserSession command, passing it details of the user whose sessions you wish to revoke.
Once you have done this, any future requests to SharePoint Online will require re-authentication:
Brendan Griffin - @brendankarl