Nucleus is a Content Management System (CMS): a powerful set of PHP scripts that allow you to maintain one or more weblogs or online journals. A short summary of the most important features is given below:

• Runs on your own server
• One or more weblogs, even on the same page
• Plugin-interface to add extra functionality
• Comments
• Archives
• Categories
• Search
• Multiple authors
• Future items
• Drafts
• Extensive administration area
• Media library and file upload
• Fully customizable skins and templates
• Skin import/export
• Banlist against commenting system abuse
• RSS syndication
• Easy installation
• Easy backups
• XML-RPC interface (implementing the Blogger API and metaWeblog API)
• XHTML-ready
• Tools to import Blogger and GreyMatter blogs
• ...

Requirements in order to run Nucleus: (If you don't know if you fit the requirements, ask your system administrator)

• PHP (version 4.0.6 or higher)
• Access to a MySQL database (version 3.23.38 or higher)
• Some HTML and CSS knowledge, to edit skins and templates

Nucleus is intended for the people that want full control and 'tweakability' over their sites. If you're just looking for a very simple way to put up a site, or don't know any HTML, you might want to use a 'simpler' service such as Blogger.