expensive keywords?

[Preargirm]

Isn't it great to see payouts being made? Right now very bad, I have no more egold....prehaps till a few more days then I joined. Currently, the tide here seems alright.

[hugo guzman]

Paid again!!!
Thanks admin!!!
I'm very happy today!!!

[himoacs]

I want to earn more from adsense and I have heard that you need to learn more about high paying keywords to increase your earnings.
Thus, I tried looking for such sites and I found a lot of them with a list of some high paying keywords. However I did not understand one thing.

How do these people know about high paying keywords and do these lists get updated?