Rapidweaver - A WYSIWYG web editor for mac.
CKEditor - Real-time collaborative future-ready rich text editor
BLOCS - Visual web design app.
TinyMCE - TinyMCE is a content editor that functions as a plug-in for Wordpress websites.
EverWeb - With EverWeb, anyone can create a professional website just by dragging and dropping.
Trumbowyg - Feature-packed WYSIWYG editor in only 15kB of JavaScript