Textpattern is Open Source software that orchestrates your content (text & imagery) on the web server.
Think WordPress, but nimbler and more secure.
Out of the box, TXP has many nifty features including Textile formatting, a markup engine which allows you to express yourself without having to bother with HTML tags.
If default functionality doesn’t cut it, TXP is massively extendible using a wide range of 3rd-party ‘plug-ins’.