nginx [engine x] is a HTTP server and mail proxy server written by Igor Sysoev.
mod_pagespeed is an open-source Apache module that automatically optimizes web pages and resources on them.
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.
A family of standard web feed formats used to publish frequently updated information like blog entries, news headlines, audio and video.
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".
Open graph description entity tag
The Open Graph protocol enables any web page to become a rich object in a social graph, a open protocol supported by Facebook