A funny - but real, it seems - 1944 memo warning against the use of gobbledygook in memoranda. Seen on http://boingboing.net/2016/04/29/1944-memo-from-manager-sick...

According to http://www.futilitycloset.com/2016/04/29/clear-purpose, this is the first known usage of gobbledygook to refer to obscure jargon.