How many adsense ad blocks can you place on your webpage? According to google, you are allowed to place up to 3 ad units+2 link units on any single web page with content. So then, how will you explain the following webpage?

This is a screenshot of a local newspaper website from India. If you check the source code they have only 3 ad units. But they are 120×600 ads.

This is how did the trick.
1. First they have created a page with just two ad blocks. You can see the page here.

2. Next they called the above page twice on their regular content pages through iframes.

3. Use the power of CSS to display the ads close.
Sneaky!

The sad part is that most of these sites will not be punished by google since they are considered as authority websites. If a regular webmaster does this, then he is banned from adsense. Way to go!!