“Walken” towards responsible tweeting?

In the early hours of this cloudy Friday the 13th I discovered the literary genius of actor Christopher Walken … on twitter. My eye was immediately drawn to a March 6th tweet that read:

“An escalator in Grand Central Station is out-of-service. I stood on it for a minute or two in the name of subtle irony. No-one else did.”

As I take a gentle leap into the world of social networking, specifically twitter, I offer two questions: Is substance relevant? and What defines responsible tweeting? In a forum where Britney Spears, Paris Hilton, and Milli Jacobs are being followed by people that also converse with Steve Jobs and Steve “Woz” Wozniak, I have to wonder how anyone can offer anything of substance in a mere 140 character space. 

So I turn to you all for answers … what constitutes quality tweeting and has the world of social networking substituted substance with immediacy?