I used 500,000 articles from wikipedia to have statistical data about the words usage. With this data I applied the Markov chain for text and other custom made algorithms and created a wordpress plugin. This plugin allows a user to generate unique content based on user given keywords. Also, the user can set the keywords density as well as word count. The content works great with adsense (the ads are related to the keyword the text is created on), but it's not 100% human readable. I'm still working on it. So, I was thinking if anyone would be interested in buying such a plugin or you'd be more interested in buying an API key and do whatever you want with the data .