Do you get this?

I've asked a lot of people, many people don't, or at least they think they do, but are missing a major part of it. Anyway, the people at Private Eye obviously got it because they published it, even though the drawing isn't much cop. If you're not sure you get it, then click here and all will become clear. But you probably won't need to do that, will you, because you're all brains, aren't you?