PHP is a widely-used general-purpose scripting language that is especially suited for Web development and can be embedded into HTML.
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.
Sites who has this tag are verfied by google to use WebMaster tools
Google's hosted library for web fonts. Allows websites to choose and use fonts from a free, wide variety of fonts.