Web content management and blogging
phpMyFAQ is an open source FAQ system using PHP and available for many databases.
ProcessWire is a free PHP content management system and framework (open source CMS/CMF) built to save you time and work the way you do. Stop trying to bend other open source CMS platforms to your will – ProcessWire provides simpler and stronger control over your pages, fields, templates and markup at any scale.
ImpressPages is an open-source PHP framework with built-in content editor. Features include MVC engine, inline editing and drag & drop interface. It is distributed under the GNU GPL v.3.0 and MIT licences.