Lately, I have noticed an increase in my Adsense earnings. I am not exactly sure why, a little extra traffic is helping but the trend does seem to be moving up.
I have no idea, but perhaps Google is paying advertisers more. I no longer read webmaster forums so it is difficult to know if other adsensers are experiencing the same. There are definitely more advertising programs competing with Adsense for space on websites, than when Google first launched adsense.