Web
From Just Solve the File Format Problem
- ActiveX
- Atom (syndication 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)
