CMS-db: Open source content management system (aka CMS) without a database, it uses TinyMCE to edit pages, a what you see is what you get website editor. CMS-db is written in PHP, it isn’t resource intensive and parsing of pages is fast.
gpEasy: Lightweight CMS without the need of a database, flatfile storage suitable for personal and commercial sites, gpEasy doesn’t require HTML knowledge to edit the site, it uses a WYSIWYG page editor (CKEditor).
GuppY: Flexible and modular CMS software written in PHP to create a web portal that requires no database, multilingual turnkey blogging or CMS software with fast page rendering. Community plugins and external scripts extending GuppY capabilities are available.
GetSimple CMS: Specifically built for small websites, GetSimple doesn’t need any complex mySQL database to run, appropriate for big scalable sites, GetSimple uses XML for data storage. Its main features are customization, plugin support, easy interface, security, easy to set up, well documented and a great community.
CMSimple: Tiny open source CMS of less than 100Kb in size, it doesn’t need a database to run and it is very easy to install in your server. You can edit pages using HTML or with the WYSIWYG editor, this content management system will suit small sites.
Lightweight WordPress alternatives
RuubikCMS: Intuitive CMS software, easy to install and customize, it uses the self-contained, serverless database engine SQLite for data storage, any web server with support for PHP can host it. RuubikCMS creates friendly URLs that can be smoothly crawled and indexed by search engines, suitable for small and medium traffic websites.
TextPattern: Content management system for bloggers, small disk and memory footprint, easily extendible with hundreds of plugins. Minimalist and efficient admin interface, antispam system, optional password protected articles, human readable URL for search engine optimization purposes. Suitable for individual bloggers as well as corporations.
FlatPress: Standard compliant open source blogging platform that runs a WordPress like blog without needing any MySQL database, multilingual extensible. The data is stored in text files, you just need a webhost supporting PHP.
GeekLog: CMS PHP/MySQL based blogging software for managing dynamic web content, support for scheduling posts, comments, trackbacks, multiple syndication formats and spam protection. A huge range of community developed plugins can extend its functions.
Habari: Supports multiple database backends (MySQL, SQLite, PostgreSQL), it can be extended with plugins and the appearance changed using different themes. There is a WordPress importer for those wanting to easily change blogging platform.
NucleusCMS: Lightweight customizable blogging platform for selfhosted hosts, it needs PHP and MySQL to run. NucleusCMS has a multilingual interface, skins, basic statistics, built-in commenting system with karma voting, community developed plugins.