Yes, it means there is no limit to the number of websites you can control using the WHM/cPanel control panel. The only limitation would be the server hardware involved.
Sorry, feel I need to clarify this post more. Your first post seems to imply that WHM/cPanel will allow to register domains through the software. That is not the case, which is why we were confused by the first post. You register the domains through a domain registrar such as GoDaddy or Network Solutions. You can then set up WHM/cPanel to host and control that domain on your server. But there is no limit to the number of domains you can control through cPanel, and I do not believe there is a TLD that does not work with cPanel.
Hope that makes it more clear.