Reading #3-On the internet, nobody knows youre a dog

When I look at this cartoon, I think to myself that I am missing something. Is it as simple as it sounds, or is there something underneath the surface that I am missing? As far as what the cartoon is actually saying it is kind of funny, because I always think about that when I am playing poker online, nobody knows anything about me except that my screen name is mattymatt151. No idea where I am from, no idea what I'm doing, no idea what I look like, and no idea how old I am. You never know who you are talking to unless you are talking face to face. Even over the phone it could be somebody you're not expecting. I guess it makes you think about things and think about who you are talking to, that is of course if I am interpreting this comic the way I am supposed to.