"These “domain parking” pages were immensely profitable, generating north of $100,000 per day, according to a former Demand exec who requested anonymity. “That’s $35 million-$40 million per year without doing any work,” the exec said."

Separate point domain parking pages (have much experience here) have fallen greatly over the years. Portfolios of pages used to sell for multiples of future earnings as people didn't realize how mercurial that situation was. Once again your destiny is determined by a few big players who have very little transparency (and in all honesty their own issues with fraud to deal with).

I have seen parked domains that earn perhaps 1/5 to 1/10th of what they did in the last decade. (As one example a domain related to mortgages used to earn perhaps $500 per month back during the boom and now I'd be lucky to get $50).

Not only that but both yahoo and google can ban a domain parked page if they feel there are fraud clicks. You don't get a reason and there is practically no accountability or appeal process.