Radio UserLand is an amazing piece of software. I don't think it can be described in any single step. Here are a few ways to look at Radio from a technically educated standpoint. For additional information, browse the Radio directory or ask Radio search.
 Radio is a desktop web publishing system.
 Desktop based ...
 ... Web published ...
 ... Through upstreaming.
 If security's your concern.
 Radio is a content management system.
 At the core is Radio's object database.
 The site's structure is a hierarchy of local folders and files.
 HTML pages are generated via templates.
 XML files are published as well.
 Publication timing and extent.
 Radio is also a news feed aggregator.
 Radio is an outliner as well.
 Radio is an open development platform.
 What to do next ?

Radio Directory view OPML

preview nodes
hide wedges
activeRenderer News view RSS
 Radio Upstreaming Beta and activeRenderer
 activeRenderer Users Gallery Update
 Outline link macros
 With the webOutliner tool installed...