It's a sign.

A little something for my desk at work.

Edit: Okay, maybe this was a little inside. My boss called me into a conference room (because we all have cubicles) to discuss my training when she mentioned that there have been numerous complaints about my reading webcomics while at work. I pointed out that this is what I do on my lunch break, during which many people hover around my desk to give me stuff to do. So my boss suggested I display a sign while I'm at lunch so that there isn't any more confusion.