AB Meta is a simple, RDFa-based format for annotating pages that are about things.
If you need to convert files from one markup format into another, pandoc is your swiss-army knife. Need to generate a man page from a markdown file? No problem. LaTeX to Docbook? Sure. HTML to MediaWiki? Yes, that too. Pandoc can read markdown and (subsets of) reStructuredText, HTML, and LaTeX, and it can write plain text, markdown, reStructuredText, HTML, LaTeX, ConTeXt, PDF, RTF, DocBook XML, OpenDocument XML, ODT, GNU Texinfo, MediaWiki markup, groff man pages, EPUB ebooks, and S5 and Slidy HTML slide shows. PDF output (via LaTeX) is also supported with the included markdown2pdf wrapper script.
This site provides a collection of schemas, i.e., html tags, that webmasters can use to markup their pages in ways recognized by major search providers. Search engines including Bing, Google and Yahoo! rely on this markup to improve the display of search results, making it easier for people to find the right web pages.
Textile is a simple text markup. Simple symbols mark words’ emphasis. Blocks of text can be easily tagged as headers, quotes, or lists. A Textile document can then be converted to HTML for viewing on the web.