WordPress is a mid-level CMS. It offers some of the complex features of high end CMSes, but stays relatively easy to use like some of the low level CMSes.
As a web application, you must run WordPress through a server. Clicking on a file on your local machine will not yield any positive results for you. WordPress requires a PHP enabled server with MySQL.
It originally started out as a blogging software, however it is used for much more than just blogging now a days.
One of the most attractive features of WordPress is that it is free to download an install on your server. As such, it is estimated that 20% of all websites run WordPress. It’s not just your personal sites that run it. You can look at WordPress’s Showcase of large sites which use WordPress as well.
WordPress allows you a lot of control at the site level, such as being able to mark pages as private so only registered users can access the page. It also allows for different levels of user controls for the site. However, all access is site wide. You cannot, out of the box, restrict access to different parts of the site based solely upon the user.
WordPress also allows you to work on many levels of the design of the website, from with the admin center. So you can create menus, place widgets, etc, without the need of editing the theme.
You will often hear people talk about WordPress “out of the box”. This is because one of WordPress’s most used features is it’s extensive plugin ecosystem. WordPress has made it easy for third party developers to create extensions to WordPress in the form of plugins.
These plugins allow you to change the way WordPress works, adding functionality which may be difficult to include inside the main project for a variety of reasons.
Because of the ease of creating plugins for WordPress, there are thousands of them in existence. Some are free, while others are listed as premium. Premium plugins have a fee associated with them and is paid to the author. This fee may be a one time fee, or an annual usage fee. The fee may be from a few dollars, to hundreds of dollars – all depending upon the complexity and the authors.
WordPress also allows for developers to create themes. Themes are used to display your webpage to the end viewer. Themes are relatively easy to create, therefore there are thousands of them available. Most themes are free, although there are some that have a fee associated with them. A theme may range in price from $4 to several thousand if you have a custom theme built just for you. Most premium theme you will find are under $100.
.Org vs .Com
WordPress is broken into two parts.
WordPress.Org, allows you to download WordPress to your local machine, and also provides documentation, online help, and a way to search for free themes and plugins. With WordPress.Org, you must provide your own hosting service.
WordPress.Com provides you with a free account and hosting for your WordPress website. The hosting is provided by Automatic (they kind of oversee WordPress development), and they have different levels of hosting. Host runs from free to several hundred dollars per year for standard accounts. They also have VIP hosting which can run several thousand dollars per month, but that is designed for large clients who get millions of visitors a day.