In researching your very same line of thinking ( and I spent hours thinking):
you would need in excess of 10000 machines, due to google's pattern matching, and each machine has to have a surfing history of at least 45 days to 200 days.
if you pay attention to a lot of the little details, google has java scripts all over on web sites, so they know click habit's, mouse movement (eyeball attraction issues ), surfing habit's of most humans ....
so you would need an install base of at least 10,000 machine in which all those machines were working ( surfing ) different topics, but in the winter time they looked at vacation rentals in Florida, medicine for different medication,...
You would have to spend time looking at demographic data, you would need to surf all your ip's to the local ip's news paper, and just about everything else.
overall, to not get caught by google, my results were as follows:
a) 97500 machines all with google toolbar attached
b) about 400 web sites covering the most common topics, mostly using rss feeds to add content
c) I would be like a virus within the machine that only when certain keyword topics look-up's happened my site would overwrite the google results or redirect the google results to my pages.
d) I would have all the machines activate in a random pattern ( they would call in while the machine was surfing, then let them be active ( virus working ) for 2 hours then dead for 3 days
e) I would only let my sites hit google results only 4 times per month, never repeating the same site twice to the same machine in 5 months. 4 hit's is more than enough when you have about 100K of machines in control;
at the end of 12 month your monthly results should look like.
100K machines * 1click ( at .25 ) = 25K in revenue.
reinvest the revenue in new web sites and new machines, you'll be king of the block.
Please note, that you would need to do some serious SEO work to those sites, this will attempt to hide ( and increase revenue ) the clicks in the noise.