I am pretty sure US clicks pay the highest, then it would be UK or Canada. IM is generally more profitable with the US market.
Judging from my affiliate marketing experience, UK should be good for adsense, I expect US to also be high
It really comes down to doing your own tests. From my personal experience on one of my niche blogs, Canadian traffic provides the best EPC. However the amount of traffic is minimal compared to that of US visitors. So less is more... or more is less?
traffic from USA make high CPC (cost per click). one day, my only 1 click make $ 8.09. my average click cost is around $ 2.00
lol of course US and UK traffic pays well. Recently i have noticed that traffic from Australia, Canada and some European countries pays pretty good as well, because people from these countries buy online a lot and that is exactly what buyers look for, so...!!
Excellent answer...I was scrolling down through the responses to see if anyone would bring this up. A click on a low paying niche in the US could be exceeded by a click on a really good niche from the Island of Yap. Course, instead of saying "I got $3.89 for single click" you'd have to say "I got a really big *ss round rock for a single click"
I completely agree... It depends more on the niche as some advertisers in certain niche do offer very high CPC rates, irrespective of the country of traffic! Regards, RightMan