The last in lists: paidContent has come out with its 50 Most Successful Digital media companies in the United States. The top three are really no surprises: #1 is Google, followed by Yahoo (whose sites get a staggering 630 million unique visitors a month!) and Apple.

Then the results get a litle more interesting. For example, Zynga, whose lineup of social games—including CityVille, FarmVille and FrontierVille, makes more digital media money ($850 million!) than Amazon ($600 million), Groupon ($480 million), and the New York Times ($390 million). Note this is just digital revenue we’re talking about here, but seriously. Are those games even fun?

Another surprise on the list: Ancestry.com. Apparently “more than one million people pay as much as $159 a year to access Ancestry’s archive of digitized historical records, which they typically use to build family trees.”

Guess we have a lot of time on our hands.