nginx [engine x] is a HTTP server and mail proxy server written by Igor Sysoev.
Varnish is an HTTP accelerator designed for content-heavy dynamic web sites. In contrast to other web accelerators, such as Squid, which began life as a client-side cache, or Apache and nginx, which are primarily origin servers, Varnish was designed as an HTTP accelerator. Varnish is focused exclusively on HTTP, unlike other pro...
A family of standard web feed formats used to publish frequently updated information like blog entries, news headlines, audio and video.
A canonical link element is an HTML element that helps webmasters prevent duplicate content issues by specifying the "canonical", or "preferred".