Twitter - signboards on steroids is all

"A way to think about Twitter", .my friend Richard Ford explained, "is that it is like a bunch of tiny radio stations all broadcasting at the same time. You can tune in to whatever you want to listen to. This helps, but I'm,also thinking it is becoming like those ubiquotous sign boards that are used for advertising businesses, community organizations, and churches. Yes, there is a church in my neighbourhood that I pass regularly and they always have one of those smarmy cute little sayings about life or god or something or other. Some of them are pretty good and get you thinking, but for the most part they're just advertising. These boards only have a few lines to grab your attention and deliver the message. Hmmm - I wonder if this is where 140 comes from?