The token issuer id mismatch causing your add-in to fail may have more than meets the eye.
Quick tip on how to ensure your custom page layouts show up in the SharePoint 2013 Design Manager
When properly configured, SharePoint can allow multiple users to collaborate on a single file in real time! Learn more with this quick overview video.
How things are displayed in Quick Launch menu depends on more than whether they are marked to be shown there.
How I learned a valuable (and painful) lesson in preparation during my presentation to the Triangle .NET user group.