Three Adsense Link Units Per Page
There are two major changes to AdSense:
(1) Google now requires AdSense publishers to comply with “the spirit” of the AdWords Page Quality Guidelines.
(2) You can place up to three link units on a page.
Number one might hold a few valuable clues about how to make more money out of Adsense, as Google continues to clamp down on junk content.
TechDuke
Up to 3 link units per page is I think old. Yup, Cutting down the competition will increase the bid prices.