When you use rating to sort series (http://www.mangaupdates.com/series.html?orderby=rating), the Bayesian average is used. However, frequently an individual series manages to secure an extremely high ranking by having its "pure" average listed in the "Rating" column. This disappears when you visit the series's page, and the series goes back to using its Bayesian average to compete.

Here's a picture. We see Fukuyadou Honpo at the top: http://img339.imageshack.us/img339/2761/seriesz.png

But Fukuyadou doesn't have a 8.6; it has a 8.28: [img]http://img233.imageshack.us/img233/2707/individual.png[/img]