Some posts and screen names have it, some don't. Why is that?

It means that you read the post and nothing new has been added I believe.

Jon

Jon, now that you say that, I think it is the opposite of what you said. Red means there are new posts under the topic. Still don't know what the red screen names mean.

Red anything means you have clicked on it sometime since the last time you cleared your internet history.

How do you clear your internet history?

-->Start
-->Settings
-->Control Panel
-->Internet Options
-->Clear History

It is also a good idea to set an automatic purge for this option.
It is also a good idea to Delete Temporary Interet Files and Cookies from time to time.

In my best Homer Simpson voice

"mmmmmmmm....cookieeeees"



Good thing I'm easily entertained...