I Am The Internet

There's a fortress in the middle of a wasteland. A guy turns up at the gate and the guards say, "Who goes there?"

Guy: I would like to come into your fortress.

Guards: Well, we can only take in people who are useful to us.

Guy: I think you are going to find me useful, for I am the Internet.

Guards: No, you're not.

Guy: Yes, I am and I can prove it to you.

Guards: Go on then.

So the guy takes up bits of paper and says, "I bring you pornographical images and the rantings of angry teenagers."

The guards think about this for awhile and say, "We have one question, if you can answer it, we will accept that you are the Internet and let you in."

"Ok", replies the guy.

Guards: We are interested in purchasing hot-water bottles shaped like cats ...What else do you think we would be interested in purchasing?

--heard it on the Infinite Monkey Cage.