Hello, to attract mass traffic coming from the US is the best strategy for adsense earnings. To know what's hot at the moment, check out this list http://3pdf.com/?100=hot It's a list created in real time from google trends over the past few days. If you produce content about the 3 or 10 first topics, this WILL generate a lot of traffic soon. Try it for just one week, everyday write one or more articles about those topics and tell me the results you've got.
I'm talking about earnings, not highest cpc. US has more traffic, so wins. I don't know when google hot trends will be available for other countries.
Its a nice idea to follow and I am sure we will get enough traffic. If we are maintaining a website for healthcare and If google trends shows high traffic for technology keywords, then should we create a new website for that niche? If so, Is it possible to create a website for each category? Won't that be costly?
It is nice to create new site with popular keyword but I prefer to stick with my current sites anyway I will try to spend one hour/day to test new site with new keyword.
One hour a day is already a lot, if you can keep your word for 30 days, you'll see good results for sure!