"Flat earth theory is still around. On the internet and in small meeting rooms in Britain and the US, flat earth believers get together to challenge the "conspiracy" that the Earth is round.
"People are definitely prejudiced against flat-earthers," says John Davis, a flat earth theorist based in Tennessee, reacting to the new Microsoft commercial.
"Many use the term 'flat-earther' as a term of abuse, and with connotations that imply blind faith, ignorance or even anti-intellectualism."
"Mr Davis now believes "the Earth is flat and horizontally infinite - it stretches horizontally forever".