As I reported at Search Engine Land today with Google Updates AdSense Program Policies, Google AdSense is now allowing three link units per page.
So what does that mean? Well, I can have three of these on a page.
That is one, here is a second:
And the last, but not the least.
These link units are different from Google's normal AdSense units. If you click on them, they will take you to a page of ads, as opposed to an advertisers site. In a sense, two clicks are required to reach an advertisers site.
Forum discussion at WebmasterWorld.

Comments:
Joost
06/07/2007 01:56 pm
Why should I use link units?
ClassTalkers info blog
09/30/2011 01:42 pm
their good for little places other ads cant go