This is an (ancient) IBM internal memo that was not sent to all employees.  It was an IBM Field Service Bulletin that had been posted to the IBM service database as a joke by one of the field engineers, who was subsequently fired for it.  How do I know?  I was working as an IBM Systems Engineer when it happened, at least 20 years ago, perhaps earlier.

Oh, and even Snopes has it recorded, though they don't say it was a real memo... but I assure you, it was.