This guy earned literaly half million dollars, almost $600,000 dollars with Adsense during 7 years! It's a result of years and years of hardwork. He gets traffic through search engines and PPC. He's averaging $100-$150 a day with about 6,000 uniques per month. That mark was about $1500 daily with Adsense few years ago. The key of success is patience, very quality content, writing, writing, and more writing. Another thing written in his post on forum is choosing variety of niches, so the only few of them could generate awesome Adsense income, while the others will be below average.
Other report show new Adsense interface. You can now track the graph of earinings compared to number of clicks, pageviews, CPC (cost per click), RPM (former eCPM). Additional features like earnings per week or month allows to compare your revenue much easier. You can track income by ad sizes, types, bid types or via countries or products (e.g. Adsense for Domains vs flash ads targeting type). The main page of new Adsense interface shows todays earnings, yesterday, this month, last month earnings... It has much more functionallities! However, some people still use old version (like myself :). Blue color dominates on this interface that's still in beta version.