How abundant trailer section can i place contained by my adsense website?

i saw in google adsense terms 3 unit can post on a website... but, masses adsense programmers place their ads above 3 units on their variable page. is should 3 unit for one page? or per website?...
What's more profitable? ----Affiliate Marketing or Google...
Answers:    You can put PER PAGE:

- 3 units Adsense ads
- 1 section Ad link
- 1 unit Google search
- 1 section Google referralsSource(s):https://www.google.com/support/adsense/b...
Can I earn through Adsense if I've...
google help severs better answers !!
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