On.

When the little "head" icon is grey you are offline. When it is in full color you are online :thumbsup:

I have noticed that if you are on the website for an extended amount of time without activity, the system considers you offline. Clicking the first link places you back "online" but it isn't recognized in that first page load. If you were to refresh that page after seeing that, you would noticed that it would indicate you as online.