With that migration to Markdown, the rest of my old posts are kinda gonna look like shit – or are they?
Introducing Plugin Organizer, which allows you to enable plugins per-post, or even based on a wildcard URL! It’s kinda hard/nonintuitive to figure out/set up, but this question kinda explains how to use it for the purpose I want to: http://wordpress.org/support/topic/per-slug-or-per-category.
Old posts showing up in the post list view (http://blog.samsandberg.com) will still show up with Markdown-specific formatting, but for post-specific pages (such as http://blog.samsandberg.com/2013/11/06/ten-things/), I added a
Plugin Filter to match things like “http://blog.samsandberg.com/2013/” (and clicked
Also Affect Children) so that all posts from the year 2013 match, and then disabled my new Markdown plugin for those matching posts. I did this for 2012-2013, and then did month-specific ones for January of 2014 until last month.