"Google AdSense program policies allow you to place up to three ad units and three link units on any page." So that means that i can put this amount of ads on one website? Or its total amount of ads i can put? So for example i have lets say 3 websites and i want to put 3 ad units and 3 link units on each website - total 9 ad units and 9 link units. So its ok like that?
you can use 3 ad units and 3 link units on every page. you can have that many ads per page on as many sites as you like
thats not the account total or site total, thats page total. so you can put 3 ad unit and 3 link unit on every page if you want. you can also put a search box so total per page can be 7 ads all together. however, it is suggested that you only use about 2 ads per page and put them on prominent location so that they are visible. more ads you put, less you make (ads on the top position pays more and ads on the bottom position pays less. so if you have too much ads and people clicks on the bottom ads, you get paid less)
It would hardly be worth the bother if it was 3 Ad units per website. Have a look at some Google success stories such as askthebuilder.com and whatever he does, you do - add Chitika the askthebuilder.com bloke reckons he's made an additional $25,000 for signing up with them too. I'd caution against too many adverts though as it puts people off and they'll just bounce...