I am at the library, and when I went to use their free wi-fi, FireFox displays this message...

Attachment 61597


1.) What exactly does that message mean?

2.) Should I be overly concerned about it?

3.) Should I "run for my life" from the library?

I understand the risks of "free wi-fi", but that is my only option at the moment. So based on that, I'd like to understand what additional risks the screen-shot I posted above may cause.