Was my site "smart-priced" by Google Adsense? I made $16 one day, $4 the next and now $0.26 today!?

You might have been smart-priced, or you may just have bad luck (lower paying ads being shown/clicked). There is no such thing in Adsense as stability of income. Another possibility is that you've been having fraudulous clicks, and they are disregarded. Did you click your own ads? Or ask someone else to click your ads? If so, they found out. The next step is that they will close down your account.

This is called Click Fraud by Google Google is very smart in this. Placing ads on websites. 1. Why Ad Channels in Google Adsense set up tab Most of my friend misunderstood the real reason behind this. It is not only helping you which ads click by your visitors but also for Google which ads going on clicking by Visitors. So Google display very low paying ads on that channels for example I now explain you by good example If more visitors click your index728x90top ads Then google watch for few days. Suppose you are earning 3 to 10 dollars per day on that ad channels. Suddenly Google will display very low paying ads in that ads channel. Like one cent two cent .... and so on. If 10,000 visitors visit your site only you can earn even 10 dollars is the real story of Google Adsense. But there is no other way to cheat Google. Because Google Paying Genuinely and Regularly every month. So we have to compromise all these things in future also.

Google’s smart pricing feature automatically adjusts the cost of a keyword-targeted content click. So if their data shows that a click from a content page is less likely to turn into actionable business results - such as online sales, registrations, phone calls, or newsletter signups - they reduce the price paid for that click. In short, you can't avoid it, it's up to the clickers.