Question about the network connectivity system tray icon

I received a message from a friend asking about the network connectivity icon which can appear in the system tray. It's the icon of the two computer screens. Anyway, they lost their Internet connection and told me that system tray icon had the number '9' in it. I have never seen this before. I've see a red 'X' and an exclamation mark, but not a number.

Where can I find out what that number means? I cursor web search didn't help much. He's running Windows 7 Home Premium Edition (64-bit).

Thanks!

Peace...