Web


 * ActiveX
 * Atom (syndicaton format)
 * BBCode
 * Cascading Style Sheets (CSS)
 * Common Gateway Interface (CGI)
 * Domain names
 * Favicon
 * HTML/XHTML
 * HTTP
 * Internet Shortcut
 * JavaScript / ECMAScript
 * Markdown
 * Mime-type
 * Open Web App Manifest (.webapp)
 * RDF
 * RSS
 * Robots Exclusion Standard (robots.txt)
 * URLs (and URIs, URNs, etc.)
 * URL shorteners
 * VBScript
 * webarchive (HTML packaging format used by Apple Safari)
 * Web browser files (bookmarks, cookies, configurations, etc.)
 * Web server files (server configuration, etc.)
 * Wiki markup
 * WOFF

See also E-Mail, newsgroups, and forums (a number of web-based messaging/social-networking things are there)