WordPress

WordPress is a piece of software which has become the most widely used content management system and is used for setting up blogs. It is open source, licensed under the GPL, and written in PHP.
Features
WordPress allows users to create and edit websites through a central administrative dashboard, which includes a text editor for modifying content, menus and various design elements.

WordPress provides plugins which provide additional functionality through WordPress Plugin Directory. There are over 54,000+ Plugins available in WordPress repository, and they can be installed through either upload or by one-click installation through the WordPress Plugin Library.
Posts
Users can write posts into the software and other people reading the post can write comments about it.
Users
Since the release of WordPress version 4.7 the software had been downloaded more than 36+ million times.WordPress Download Counter  - Retrieved December 19, 2010
History
Version 5.8.1 is the latest WordPress release. It was released in September 2021

On May 27, 2003, Matt announced the availability of the first version of WordPress. It was well received by the community. It was based on b2 Cafelog with significant improvements. The first version of WordPress included a new admin interface, new templates, and generated XHTML 1.1 compliant templates.

In June 2010, Automattic, the company founded by WordPress co-founder Matt Mullenweg, transferred the ownership of WordPress trademark and logo to the WordPress Foundation.

 Free hosting 
WordPress can be downloaded and installed on any server with PHP installed. However, WordPress has a service for users to host blogs, called wordpress.com. It has a limit of 3 GB of free space,The Features You'll Love -- WordPress.com  - Retrieved December 15, 2010 with an option to upgrade for more. Users  cannot  add their own domain to the blog when using free option. But when user will buy one of the packages of WordPress.com, then user can use custom domain name.

 References 

 Other websites 
 Wordpress.com - A website that you can create a blog in using WordPress for free
 Wordpress.org - The website to get WordPress that you can install yourself