1) WordPress is an open source content management system (CMS) that can be used to build websites and blogs. It exists in two versions - WordPress.org which is open source and customizable, and WordPress.com which is hosted for free but with limited customization options.
2) The presentation discusses how to get involved with WordPress by creating themes and plugins, and participating in the large WordPress community through forums, contributing code, and attending events.
3) Businesses can also make money through WordPress by creating and selling popular plugins and themes, hiring out WordPress development services, or hosting private WordPress sites.