I had a bash at creating a proposal which would define notability on wikipedia as meaning that an article or topic is mentioned in a third party reliable source. I figure it should be impossible to write an article without a third party reference, as per [[WP:V]], [[WP:NOR}] and [[WP:NPOV]], and so I hope that people will consider using that as the level for notability in areas where no other guidance exists.
Thoughts welcomed at [[Wikipedia:Notability/Proposals]].