Anti-bot CAPTCHA widget that helps digitize books by providing snippets of books for people to enter the text for. Owned by Google.
Polyfill is a service which accepts a request for a set of browser features and returns only the polyfills that are needed by the requesting browser.
This site uses the viewport meta tag which means the content may be optimized for mobile content.
Google APIs are application programming interfaces developed by Google which allow communication with Google Services and their integration to other services.
A rich hosted Exchange environment for every user without having to manage a server.
Allows a website to define how a page is rendered in Internet Explorer 8, allowing a website to decide to use IE7 style rendering over IE8 rendering.
UTF-8 (8-bit UCS/Unicode Transformation Format) is a variable-length character encoding for Unicode. It is the preferred encoding for web pages.
Meta descriptions are HTML attributes that provide concise explanations of the contents of web pages. Meta descriptions are commonly used on search engine result pages (SERPs) to display preview snippets for a given page.
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.
A canonical link element is an HTML element that helps webmasters prevent duplicate content issues by specifying the "canonical", or "preferred".
The Open Graph protocol enables any web page to become a rich object in a social graph, a open protocol supported by Facebook