It used to be assumed that data was a pristine resource, freeing us from the old economy with its belching smokestacks. That was wrong.It's not on paper, so that makes it green. Some is good, so more is better.

Or maybe not. I'm talking about data. Sure, if it's on a hard drive rather than in a filing cabinet, no trees were killed. But what about the energy needed to power the storage components? And the power for the air conditioning to remove the heat generated by the storage components? Etc.

Of course, certain data elements are indispensable, and can be mined for all sorts of insights. But a lot of data is not worth keeping-some say that 70 percent is pure clutter.

So I'm heartened by a recent Gartner survey that found that 47 percent of enterprise IT managers ranked data growth as one of their biggest challenges during the coming year. To address the data growth challenge, 62 percent said they'd be investing in data archiving or data retirement by the end of 2011.

In other words, they aren't running out to buy additional storage hardware, responding to ominous messages from the vendors about a looming storage gap. Instead, they plan to confront the data as data.

Unsaid is the human element-an examination of the decision process underlying the stored data. "Why are we keeping this?" in other words. But that won't show up in any survey since there is no commercial product involved and hence no vendor to sponsor the survey.

In the old days, when data was on paper, it piled up and soon generated a crisis that demanded an obvious solution. (Admittedly, the resulting bonfires were not very green.) We may be reaching that situation in data storage. Yes, the platters have higher and higher capacities, but you still have to buy then, and having bought them there is always some way to fill them. Instead of doing that, why don't we just throw out what's unneeded?

Digital bonfires, it turns out, really are green.