XKCD Isn't Funny - #1810 - Chat Systems
This comic was probably intended to be confusing, but it succeeds a little too well. Especially compared to the other graphs that Randy's put out. Even when he was making an infographic that nobody needed or wanted, it looked planned out and designed. Not to say that Randy put zero thought into the organization of this comic, just that he put less thought into it than we've come to expect.
I really like the double 'wall' bit, but that's the only joke, and it makes the rest of the comic seem like just setup, when it could be much more. Well, not that much more, but still more than what it is.
Maybe if it was more driven by narrative. Like, a guy could be meeting up with a Skype friend for the first time, only to realize that they lived in the same apartment. That's a weak example, but still. And then the wall gag could be the alt-text. It'd say something about the tiny invisible connections that make up our world, like the guy who dates the girl who serves you McDonalds is also friends with your uncle. Maybe I just want everything to be Cloud Atlas.
Also, if I were the type of person to do sick burns on Randy, I'd say like "you can tell he's making this comic up because there's no way he has this many friends".