You write a post in your space. Then it gets popular and has good traffic (including SEO traffic). Other space owners could be interested to have a unique right to have your post in their space. Because then they will get the traffic they are interested in from your post to their space. So it would be nice to be able to sell ownership of your post to another space. Once the part sold, it's moved to the buyer's space (new owner). Plus blockchain remembers (shows) you as the author of this post. And new owner can resell the post.