If TGPs weren’t making money then so many people wouldn't be doing them. As with everything, if you know what you're doing you can make money.
Asian traffic being hard to convert is a myth propagated by ignorant webmasters. Obviously if you try and promote an English sponsor to a Japanese surfer you'll never convert BUT if you promote a Japanese sponsor (e.g.:
http://click.dtiserv2.com/Click/1039-99-us938) you'll make bank. I should know, I predominantly work in the Asian niche and 1/3 of my traffic comes from Asia.
[spam]Use a foreign sponsor with the script in my sig and I can almost guarantee you'll see an instant increase in your profit margin.

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