You know the little green light that is under the username? (See picture).
If it lights up green, this tells us the user is online. If blue, the user is offline. I think Yoda's picture just tells us he's online all the time!

By the way, most Yorkies with silky coats show up with green eyes when a flash is used. Some cameras reduce this effect, and you can eliminate it if additional room lighting or spotlights are used. However, many of us have grown to love the look.