Robin Good: Cleeng is a service that allows content publishers to monetize their content by placing certain sections or specific content items on their site behind a paid wall. Payments can be made in one-click and Paypal, major credit cards, SMS payments are all supported.
"Cleeng patented solution allows publishers to hide specific part of their content between two tags: for example a blogger can monetize an entire article or just a part of it, a novelist can cover just a few pages.
With Cleeng, you define which part of the content is available for users and the price for each item of content.
When published the content item is hidden behind a secure Cleeng layer on your website, so the page remains completely visible to search engines."
Key features: http://cleeng.com/us/features/
Find out more: http://cleeng.com/