From the master of short posting, Seth Godin:
An appropriate illustration,
A useful topic, easily broadened to be useful to a large number of readers,
Simple language with no useless jargon,
Not too long,
Focusing on something that people have previously taken for granted,
That initially creates emotional resistance,
Then causes a light bulb go go off
Causes the reader to look at the world differently all day long.
I’m learning. I need more other media. I need pictures. I need to figure out how to post audio. More importantly, I need my video camera back.