I recently submitted a puzzle with the 'knowledge' tag. It was automatically changed by the system to 'trivia'.
When did this happen?
Do we now consider all knowledge to be trivia?
Should the 'knowledge' tag simply be deleted if it is no longer allowed?
EDIT 13 Oct 2015
For clarity, here is a definition
details, considerations, or pieces of information of little importance or value. "we fill our days with meaningless trivia"
Since all trivia is knowledge but not all knowledge is trivia, I suggest that the more general 'knowledge' would be a more apt tag to keep. The trivia tag is too restrictive and should no longer be the default. Instead I propose that 'knowledge' should.