At some point in the distant past, a professor in a networking class at some unknown university drew a diagram that looked like this to represent two machines talking to each other over the Internet:

The cloud in the diagram indicated that the Internet was a shapeless, almost immaterial transport medium. In the words of Craig Burton, the Internet was a Giant Zero, a "hollow sphere: a giant three-dimensional zero." Whether it's a cloud or a giant hollow sphere (harder to draw), the Internet is a place where every node is functionally the same distance away from every other node. On the Internet's hollow sphere, we all live on the surface, pulled by it's unique gravity to the center.

Sometime in the last decade, someone else drew this picture of a cloud:

The cloud in this diagram may look the same, but it's quite different from the one in the previous diagram. The cloud in the second picture isn't a hollow sphere, a giant zero. Rather, it's a destination. A place where servers live. It's immaterial in the sense that you can't touch the servers delivering you service. But it's a place, not a path.

The distinction is important. In the first diagram, the computers are peers and the cloud connects them. In the second, the computer is a client to some invisible server hiding in the Cloud.

This isn't to say the Cloud is bad. Lots of goodness there that I use every day. But we shouldn't let our love affair with the Cloud make us loose sight of what makes the Internet special.

The Internet is open. By and large, the Cloud is not. Openness means that the Internet is interoperable, based on standards, and governed by agreements and processes that are more transparent than those of a private company.

Anyone can play on the Internet. In the Cloud you are in someone else's domain and have agreed to their obfuscated terms and conditions. While you have to pay for transport and an address on the Internet, those are commodities that are available from a wide variety of providers.

On the Internet, you are a peer. In the Cloud, you're a client. On the Internet you are zero distance away from every other node on the Internet.

The Internet is a vast, vibrant, diverse ecosystem. The Cloud is one, relatively tiny part of the Internet, a monoculture of protocols and business models.

The Internet is possibly the most amazing feat of decentralized infrastructure humankind has ever accomplished. The Cloud is a nice model for building useful businesses.

So, next time you see a cloud diagram, remember that you can draw it in two ways, and those two models have very different properties.