nginx [engine x] is a HTTP server and mail proxy server written by Igor Sysoev.
Phusion Passenger - a.k.a. mod_rails or mod_rack - is a web server and application server, designed to be fast, robust and lightweight. Administration tools allow you to gain insight into web application operations and server performance.
Ruby on Rails is an open-source web framework that is optimized for programmer happiness and sustainable productivity. It lets you write beautiful code by favoring convention over configuration.
Rack::Cache is a component to enable HTTP caching for Rack-based applications such as Rails.
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.
This page contains a meta robots tag which tells search engines and robots to index or not index the page.