I have been using WordPress for almost more than 5 years now.
I will explain in below post step by step procedure to harden, secure & optimise WordPress for best performance & security.
So First thing first,
Introduction to WordPress
What is WordPress: WordPress is a free and open-source content management system (CMS) based on PHP and MySQL. Features include a plugin architecture and a template system. WordPress was used by more than 23.3% of the top 10 million websites as of January 2015. WordPress is the most popular blogging system in use on the Web at more than 60 million websites.
As we know of today WordPress is offered in two different formats, One is managed & hosted by team at WordPress.com & second as self hosted by user using downloadable installable package available at WordPress.org.
Difference between WordPress.com & WordPress.org
Following things really differentiate WordPress.com and WordPress.org from each other
WordPress.com: User provides the content & website is managed by team at WordPress.com
WordPress.org: Content provided by User & Managed by User itself