XML Copy Editor - XML Copy Editor is a fast, free, validating XML editor.
ConnectedText - ConnectedText is a powerful but simple information management system.
Altova XMLSpy - The XMLSpy XML Editor is a powerful tool for editing XML and related technologies. It is the only XML Editor with patented SmartFix validation, enterprise-grade editors, converters, debuggers, and code generators.
TiddlyWiki - a non-linear personal web notebook
footnote - A beautiful, fast, and simple note taking app in the style of elementary
wikidPad - wikidPad is an application for storing thoughts, ideas, todo lists, contacts, or anything else that user can think of to write down.