There’s lots of talk, and confusion, about the “cloud” and “cloud computing.”  I’ve recently contributed to it (the discussion, at least, and possibly the confusion) with some of my worries, and in some technology and vendor circles that’s been seen as controversial. I wanted to share some thoughts about just what the cloud is – because for the purposes I care about, it covers much more than people think, and I’d hate for debates about this stuff to get hung up on semantics about what counts as cloud and what doesn’t. By understanding just how broadly the features we associate with cloud computing are entering our lives, we can see the importance of maintaining freedoms that it otherwise naturally tends to diminish.

There are a few definitions out there – not surprising, since “cloud” is a metaphor that could work for several phenomena.  One, known in Internet engineering circles, refers to the “middle” of the Internet – that place amidst the hops data can take from sender to receiver that is remote from both of them. A second definition thinks of cloud as “swarm” – so distributed computing or data storage, where lots of computers might host a bit of code (think SETI@home and Harvard’s IIC) or data (think Tribler). (Interestingly, this is the opposite of the first definition: it contemplates everything but the middle.)

A third definition, more in use in discussions of the cloud today, speaks to an asymmetry between sender and receiver: one is a client – the “user” of a service – and the other is the service itself.  Examples are you and your gmail (your mail is stored in “the cloud,” in that case at Google); an online Flash game at sites like FlashArcade; and Microsoft’s “Office Live,” where your documents and spreadsheets are both stored and used online with Microsoft.  The latter is sometimes called software-as-a-service (awkwardly, “SaaS”), denoting that the code for it is running in a central place – where a vendor can shape and update it at any moment – rather than on your own PC or other device.

This idea of cloud computing is increasingly prominent because it’s finally attainable. For many people Internet access is ubiquitous and continuous. With Net access a constant – often achieved through smartphones, where an absence of a wi-fi signal need not mean no access, since the cellular network can still be used – there’s less of a need to have a PC or other device be self-sufficient.  Data and code can be accessed and run far away, with the user barely noticing the difference, and there are lots of pluses to doing things this way, even as I’ve made the case that this shift carries risks that should be dealt with.

But there’s another factor at work that pushes outward the definition of “cloud computing.” It arises from the adoption of what I call “tethered appliances.” These are devices where the code and data may well remain near the user, so they do not at first glance fit into any of the definitions of the cloud. Think Amazon Kindles, where your books can be kept on the device (and thus accessed on an airplane without Net access); iPhones, where you download “apps” to run on your phone; and TiVos, where your recorded shows are stored on a hard drive inside the box.

But in a key respect – that of your freedom to control your code and data – these devices act like cloud services.  That’s because the vendors have privilege to say how they will operate long after you’ve brought the devices home, updating the way the devices work, and their contents, over the Internet or a cellular network. Sometimes that control is total. For example, no outside code is permitted on a Kindle or TiVo.  Sometimes it is partial: Apple allows outsiders to code for the iPhone, but code must be vetted by Apple and distributed exclusively through the iPhone apps store.  For all of these devices, it’s more like allowing Amazon and TiVo and Apple to set up a beachhead in your home (or pocket), a little server of their own that’s a cloud service that happens to be near you:

[W]e need to rethink our vision of the network itself. “Middle” and “endpoint” are no longer subtle enough to capture the important emerging features of the Internet/PC landscape. It remains correct that, from a network standpoint, protocol designs and the ISPs that implement them are the “middle” of the network, as distinct from PCs that are “endpoints.” But the true import of this vernacular of “middle” and “endpoint” for policy purposes has lost its usefulness in a climate in which computing environments are becoming services, either because individuals no longer have the power to exercise meaningful control over their PC endpoints, or because their computing activities are hosted elsewhere on the network, thanks to “Web services.” By ceding decision-making control to government, to a Web 2.0 service, to a corporate authority such as an OS maker, or to a handful of security vendors, individuals permit their PCs to be driven by an entity in the middle of the network, causing their identities as endpoints to diminish. The resulting picture is one in which there is no longer such a clean separation between “middle” and “endpoint.” In some places, the labels have begun to reverse.

So when I say I’m troubled about the cloud, it’s a shorthand for being troubled about consigning some of our longstanding technological freedoms to others. They can affect (for their own reasons or by government order) our digital environment in real time. This is comparatively new in the public’s experience of technology, even as we’ve seen forms of cloud computing within firms for years – places where we might naturally not care as much about personal freedom, since the computers (and most of the activity taking place on them) belong to the company. I don’t begrudge operators of cloud-based services from rejecting this expansion of the definition. For their purposes, it can make sense to distinguish between stuff stored at home and far away, whether or not a home device is controlled remotely by a vendor. But for the areas many of us should be caring and thinking about, a tethered appliance is tantamount to being in the cloud, and the sea change this represents has to be dealt with, especially since it’s appealing for so many other reasons – such as security and convenience.