This script (for this blog) is called WordPress, it is (one of) the most popular blogging script(s) on the web and anyone can use it for any lawful purpose including work-safe and non work-safe content. The theme I am using is the default theme but there are 1,000′s of themes to choose from.

To install WordPress just get the script off their site and follow their installation guide. You need a host that supports php, MySQL and some kind of cpanel. (I recommend 000webhost.com [also it's 100% free]).

http://www.wordpress.org/download/

If you don’t want to install it yourself you can get *yourblogname*.wordpress.com (a free wordpress domain) at http://wordpress.com, or you can buy your domain from them with wordpress automatically installed.