[Jwarder]

> The rule of thumb I use is to ask: if someone had shouted this in a supermarket or bank line, what would happen?

I can see the appeal, but I'm not sure about this. There are tons of conversations that are (to my mind) acceptable on Twitter that would be improper on other public settings.

For example there are lots of security vulnerability discussions on Twitter that I think would get you in trouble if you were loudly talking about them while waiting in line at the bank. I've seen impolite and vulgar jokes that are acceptable to share with friends who might follow you on Twitter, but would cause some pearl clutching at my local Whole Foods.

The problem (to my eye) is that Twitter is public, but public behavior isn't universal.