1) Buy something for a price.
2) Sell for a very tiny bit more.
3) Repeat as much as possible, for as long as the market sustains the price difference.
Early on in AdWords/AdSense, some sites were able to buy traffic from a cheap keyword and put up basically a thesaurus page with the higher value pay-per-click (PPC) ads more than covering expenses (eg. pay $0.05 per visit for a N visitors, then by optimizing conversions encourage click-throughs for > $2.00 each).
Later, before the online ad-market shook out upstarts, it was often possible to buy traffic from one source and sell it on another, most often to or from AdSense. Hence a proliferation of MFA sites (with almost no content but relevant AdSense links).
But not thinking too hard suggests that paying nothing for traffic, not paying less, is even better. So with an entrepreneur's ethics, I figured:
a) Business names and addresses are long tail search terms and not under copyright
b) Dense Pages of Long Tail Search Terms => Targeted, Specifically Motivated Traffic
c) (+ AdSense) => User Gets A Solution (finds a service) + PROFIT
I designed a logo, scraped some yellow pages, and it made some money. Continual earnings trumped the dreams to conquer the internet.
Incidentally, the name is a palindrome, and rotating the logo through 360 degrees both spells out "snapspans" and looks like a yin-yan:
EDIT: Somewhat erratically, as search engine rankings update every so often, it's at ~30K visitors and ~$450/month. It got spidered because of a link exchange with another more established site.
EDIT2: Probably a good opportunity to write a blog post and submit, but only if people care.