I wonder what is your impression about the earnings. I am using it on an italian language website, medicine-related and from what I am seeing in this forum, I have never gotten a really high click. Maximum 0.50, I think. I guess english keywords have much more competition and thus higher bidding. Every now and then, people here are talking about $3 or more earnings/click, things that I have never seen in my website. What do you think?
I think in English too 50 cents a click is high. I get about the same ppc in English and in Dutch - for roughly the same subject. around 12cts per click (on average). Don't mind the bragging: what matters isn't that one click that gets you 3 dollars, but the average ppc and even more important the average ecpm. And, at the end of the month, what matters is how many euro's you get onto your bank account, right? Turifungia is also right of course: you need to optimize - both placement and color-scheme and ad-block size. That can increase your CTR bigtime.
I used it on croatian site, I received some quite high clicks, over $1. Average was the same as my english sites.