Ad units per page clarification

[NibbleGuru]

I remember that we could only have 3 content ad units per page.. I am seeing more and more units on some popular sites.. sometimes even 8 units per page..

<snip>

has 6 ad units.. 2 banners (top and bottom) and 4 squares..

is this something we all can do or is it something for premium publishers only..

[edited by: incrediBILL at 9:46 am (utc) on Jan 11, 2012]
[edit reason] removed link, no outing sites please [/edit]

[umain30]

Here i have seen in a webmaster forum [i can't recall the name] that the Google Adsense partner site can place three 3 ads from their partner id and and 6 from their own id as such the page is user generated content.