I think a solution to the falling Adsense revenue situation is pretty simple, but I'm to poorly to do it. You can get an ad server that geo-targets like OpenX. that way adsense would only display for US, UK and Canadian visitors, and you can load country/language niche networks to target the visitors from various language/nation groups. You'll earn in those currencies but then you could leverage exchange rates to get a little more out of it. Here's the catch. You need to have a dedicated server for your sites. Something like $200/month. Unless someone else knows of a cheaper way?