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.
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.