Sctuctured blogging is taking many forms, but structured blogging needs structured data.  To get structured data into your structured blog (so people/systems can subscribe to your structured RSS output or surf your structured blog and do stuff with your structured data) you need a structure to target the data against when you blog - a schema.

Got it? No? Ok, here's a screencast showing what I'm blabbering on about, by Joe Reger (of Reger.com).

Via Joshua Porter (again).