I had a blog here before, and thought I’d canceled/removed it. Wanted to try micro.blog out again, re-signed up – and now there seems to be some confusion or intertwining between the old and new (sorry, this is hard to explain!) Micro.blog - @exocubic and https://exocubic.micro.blog are both showing posts under my new account. Any way to merge the two (best case) or delete the older one?
The two sites you have linked to are linked, one as your Micro.blog profile and the other as your full blog. Are those the two you want to merge?
Yes, that would be simplify things for me a lot - thanks, Simon!
Just making sure I understood, Mark. 
Here’s how it works:
micro.blog/exocubic is your profile for the Micro.blog timeline.
exocubic.micro.blog is your blog, hosted by Micro.blog, and works like a normal blog with feeds and pages and so on.
There is no way to merge them as such. You can separate the two, since the profile is made up of whatever feeds you decide to connect to it rather than creating posts for itself, so to speak (other than replies to existing posts and conversations in the timeline). You can also request to have the blog deleted and keep the profile.
Do you have a blog hosted elsewhere or were you looking to try Micro.blog as your blog?
Ah ha! I was the one who needed clarification, and your explanation has provided it. I was conflating the two, wondering why I wasn’t seeing the same posts in both locations. I get it now - thanks for setting me straight, Simon.
Glad I could help. 