Textile was the driving markup behind Textpattern (https://textpattern.com/), one of the better publishing/CMS tools out there on PHP. It had a nice object oriented approach that was less painful than Wordpress, and gave great flexibility to design aspects in ways that were easier to work with than Wordpress... but Wordpress won the popular marketshare, and TP was relegated to some diehards. Those diehards still pump out fixes and features, and it's worth a look at https://github.com/textpattern/textpattern/ if you want to see something a bit different.
Oh no, I think I may qualify as a diehard now. Or at least a long time diehard user of a diehard CMS. xD Funny to see that word.
I still use TXP at [1] and others. Back in the day when I didn't know how to code, and yet too much reliance on Joomla and WordPress plugins was often disastrous (one of those small plugin vendors sold customer data to a very specific type of telemarketing firm, as a funny example), TXP tags absolutely saved the day. You could use them to write web apps with CRUD interfaces, with the help of the admin theme being utterly simple to style away using CSS.
You could create a new section within seconds, an instant /whatever endpoint with a blank textarea where you could place any content type or any code you wanted.
For example the smd_xml plugin (thanks Stef) where you could write e.g. <tag query="SQL query here" wraptag="p">{title}</tag> to show a quick list of favorite book titles from the DB or whatever content you wanted really. Combine that with another tag for getting GET and POST variables and voila, a lot was possible without leaving the admin interface.
Toward the end of my business-oriented TXP days, I was running a network of food and drink distribution & marketing websites which spoke to each other on the back end, hosted a sales material database (labels, product shots, PDFs) along with custom PDF creation tools for salespeople which drew on that database. All without learning to do web coding...and when I was ready to code I was _really_ ready because I had already made some minor fixes to plugins, which were editable via the admin panel directly.
(Did I mention that you install plugins by copying and pasting a plain text bundle into the admin? This clipboard install method is pretty amusing and easy on the brain)
To this day I enjoy using TXP. It's very lightweight, it has a learning curve, but it works great for blogging and lots of other things. Textile and Markdown both live comfortably in the same mind and it's nice to be able to work with both.
