Can Ubuntu really run all Windows programs?

He said: "all Windows apps as a thin client". Since "thin clients" usually involve program execution elsewhere, presumably this means via remote desktop or something similar. And the Ubuntu for Android page mentions Citrix thin clients.

And of course you can run a licensed version of Windows as a guest OS in a Virtual Machine using Ubuntu as the host (which I guess would sort of be cheating because you are running Windows and not Ubuntu ;). This will work with most Windows programs, but you can occasionally run into issues with application licensing that won't run in a VM and/or hardware requirements that can't be satisfied by the VM.