I created a website for folks learning English as a foreign language: http://www.phrasemix.com

I've been running it for the last 5 years. The first 2 years, it was just a blog that I maintained for free. 3 years ago, I started selling access to audio recordings of the lessons as a subscription.

The site generates about $2K per month off of around 300K monthly visitors. It continues to grow but very slowly.