Check the HubPages forums... Google changed their algorithm which made most hubs drop from the first page results on Google... Then HubPages changed their Adsense layout... BUT you can join the HubPages Ad program now which pays per impression, not per click.
Well I asked this too. But I found out that you get 100% hubpages ad earnings and they get none. BUT Hubpages only puts your ad code on 60% of your posts so basically its still 60% 40% but not total revenue.