So if we don't register a domain name, what URL do we invite people to, and how does the Social Network and other people know what URL to enter?

If you want to invite someone to sign up for MLMv2, you can just forward the same URL you used to sign up. When you want people to view the content that makes up your campaigni, the social bookmarking and networking weblets automatically generate the link. For example, if you go to one of the blogs or landing pages you have created on MLMv2 and click on "Social Bookmark This," the URL to your blog or landing page is automatically generated and sent in both the Automated and Semi-Automated options. It is also sent automatically when using the "Share" drop-down that appears under any of your content, which will also send your content to social bookmarking and networking sites, but is not as automated.