Sadly Google never releases enough detail to allow webmasters to be pro-active with direction.
How many ads above the fold are too many?
How big can ads above the fold be?
How is "content" measured?
Once again, if Google were willing to give away a few more details, it would help webmasters build websites that Google would like to have in their index. I'm happy to remove ads if Google would not have my site in the index otherwise. I just need to know how many I can have.