1. WYSIWYG View. What-You-See-Is-What-You-Get
2. WYSIWYM View. What-You-See-Is-What-You-Mean
3. RDF Triple View.
4. Source Code View.
You can hit a [demo](http://rdface.aksw.org/test/tinymce/examples/rdfaDemo.html) to try it out. Interesting.