@smokey A couple of observations from my personal experience.
Typically when you follow a person you want to discover all of their content, so we begin to search for all of their blogs, YouTube channels, etc. Not really possible to segregate content unless you start blogging under a pseudonym.
I have been somewhat of a domain collector with over 80 domains and grand plans for each of them. Unfortunately, it’s way too much work and too much hassle for anything really meaningful to get done with so many domains. I did plan one for a blog, and for a microblog, a photography blog, one for status updates, etc. and while I did try it for a month, it was too much work. So I eventually cut them down to 5 domains in total and to just one blog, and one photography blog.
A good idea to have multiple domains, but it’s way too much work unless you have a content creation team on hand.