Websites using some form of Captcha technology on them.
Anti-bot CAPTCHA widget that helps digitize books by providing snippets of books for people to enter the text for. Owned by Google.
RequireJS is a JavaScript file and module loader. It is optimized for in-browser use, but it can be used in other JavaScript environments, like Rhino and Node.
Meteor is an open source platform for building web and mobile apps in pure JavaScript.
Facebook's Comments box lets people comment on content on your site using their Facebook profile and shows this activity to their friends in news feed. It also contains built-in moderation tools and special social relevance ranking.
This site uses the viewport meta tag which means the content may be optimized for mobile content.
nginx [engine x] is a HTTP server and mail proxy server written by Igor Sysoev.
PayPal is a American international e-commerce service that enables companies and individuals to send money and to accept payments without revealing any financial details.
Stripe is a developer-friendly way to accept payments online and in mobile apps.
UTF-8 (8-bit UCS/Unicode Transformation Format) is a variable-length character encoding for Unicode. It is the preferred encoding for web pages.
The http-equiv attribute provides an HTTP header for the information/value of the content attribute. The http-equiv attribute can be used to simulate an HTTP response header.
Google's hosted library for web fonts. Allows websites to choose and use fonts from a free, wide variety of fonts.