“Ave Position 6” but ad not showing

My keyword’s average position for today is 6.3, but the little info pop-up on adwords says it’s rank is too low to show on the first page. This is despite there being at least 8 ads on the first page when I do the search. Some times I see my ad on the first page, sometimes it isn’t on any of the pages. What’s going on?

Original post by davidtube