DoubleClick is a provider of digital marketing technology and services. Companies come to DoubleClick for expertise in ad serving, media, video, search and affiliate marketing to help them make the most of the digital medium.
nginx [engine x] is a HTTP server and mail proxy server written by Igor Sysoev.
websites using the $ symbol on their website - meaning it may accept payment in this currency used in Israel.
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.