The import should be pretty quick, usually a few minutes and probably never an hour unless something has gone wrong. The Markdown import can be a little picky about formatting, so my guess is that there was an error and it did not successfully process the import.
One tip: you can see a rough log of some of the actions Micro.blog is taking while importing at this URL if you’re signed in. That might provide a clue. Also, feel free to email me the ZIP to help@micro.blog and I can check it out.
@manton After playing around with the frontmatter, it seems like if you have a blank title: field the import fails. With blot.im, I had to use a blank title, so that the title wasn’t automatically selected.
I think if possible, a blank title should be an acceptable importable field, and can be ignored on import.
For now I can just go through and remove the title line from posts.