WordPress - blog content management
WordPress started as just a blogging system, but has evolved to be used as full content management system
Hundreds of plugins that extend what WordPress does
Cross-blog communication tools
WordPress offers a feature set with on par or better than any other software of its kind. WordPress is also committed to making the latest blogging technology available to our users (such as Trackback) and taking it a step further (such as with Pingback). You can rest assured that with WordPress you will be on the cutting edge of the technology available.
The following is a list of some of the features that come standard with WordPress, however there are literally hundreds of plugins that extend what WordPress does, so the actual functionality is nearly limitless. You are also free to do whatever you like with the WordPress code, extend it or modify in any way or use it for commercial projects without any licensing fees. That is the beauty of free software, free meaning not only price but also the freedom to have complete control over it.
Full Standards Compliance
WordPress has gone to great lengths to make sure every bit of WordPress generated code is in full compliance with the standards of the W3C. This is important not only for interoperability with today’s browser but also for forward compatibility with the tools of the next generation. Your web site is a beautiful thing, and you should demand nothing less.
WordPress comes with a full theme system which makes designing everything from the simplest blog to the most complicated webzine a piece of cake, and you can even have multiple themes with totally different looks that you switch with a single click. Have a new design every day.
Full User Registration
WordPress has a built-in user registration system that (if you choose) can allow people to register and maintain profiles and leave authenticated comments on your blog. You can optionally close comments for non-registered users. There are also plugins that hide posts from lower level users.
Intelligent Text Formatting
If you've dealt with systems that convert new lines to line breaks before you know why they have a bad name: if you have any sort of HTML they butcher it by putting tags after every new line indiscriminately, breaking your formatting and validation. WordPress' function for this, intelligently avoids places where you already have breaks and block-level HTML tags, so you can leave it on without worrying about it breaking your code.
WordPress’ highly advanced user system allows up to 10 levels of users, with different levels having different (and configurable) privileges with regard to publishing, editing, options, and other users.
Visitors to your site can leave comments on individual entries, and through Trackback or Pingback can comment on their own site. You can enable or disable comments on a per-post basis.