In the past month or so CassioburyPark.info has had around 230 page views, taken up none of my time, and has earned me £9 (~$17.90).
The site, providing basic information about Cassiobury Park in Watford, has not been promoted anywhere and does not rank highly in Google. In fact for a search of “cassiobury park”, cassioburypark.info is not even on the first page.
Despite poor Google rankings most of the traffic does originate there. However the vast majority is from specific search terms such as “cassiobury fun fair” and “history of cassiobury park” instead of people looking for general information about the park. In total 52 different search terms were used to find the site in this past month.
The money comes from matched (which is not a dating website!), an ad network that pays you £3/month per page (upto a max of pages 5 per site) for including an Google AdSense style text ad on your website.