Glacius is pretty simple. It is a Node.js application that uses SQLite for data storage. Static content and uploads are stored in S3 and served through Cloudfront. nginx is used as a reverse proxy to the Node app.
Infrastructure is deployed (mostly) with CloudFormation. This site currently is sharing resources with a bunch of other stuff I host.
mediainfofor introspecting uploaded media files
file(via libmagic) for determining mimetypes of uploaded files
I decided to use XML (mostly XHTML) as the markup text for all wiki content. Mostly because XML is very easy to parse, and since I could just write regular HTML, custom styling would be easy. Markup languages like Markdown or something similar to MediaWiki were deemed too complex and frankly I don't like Markdown very much.
When I need customization in the form of markup I create a new tag prefixed with