I'm wondering how many websites are actually successful at making money purely off ads. Clearly the search engines do, but apart from them can you point out specific sites which have successful business models that rely only on ad revenue generated from attracting visitors?
I'd be interested in any reliable data one way or the other.
Based on the responses, let me clarify: I'm looking for real data about real sites that make real money, if they exist. Please no claims without backing it up, and no stories about making several $k a year. Let's put the floor at $1 million in revenue.
Here's one example: Answers.com - $20.75 million in 2009
Anyone got anymore?