Sam Zell just told the 20,000 employees at his company that he trusts them on the Internet during work time. “I have instructed that all content filters be removed,” he told Tribune Co. workers in a memo last week. “You are now exposed to the dangers of YouTube and Facebook. Please use your best judgment. Let’s focus on what is important, and go for greatness.”

Is this guy crazy — or is he onto something?

Understand, this isn’t what we usually think of as an IT decision. Sam Zell isn’t a CIO. He’s not in charge of cybersecurity for his company. It’s not even clear whether Tribune’s IT people were consulted.

Zell is the Chicago real estate billionaire who took Tribune private last year. Now he’s the chairman, CEO and biggest shareholder of the company that owns the Chicago Tribune, the Los Angeles Times and other newspapers, along with dozens of TV stations and the Chicago Cubs.

In other words, he’s Tribune’s big boss. So when he decides that Internet content filtering will go, it goes.

What’s more interesting is why Zell thinks this is a good idea. Doesn’t he understand that unrestricted Web access will demolish productivity, clog networks, amp up legal liability issues and blow holes in security? (It must be true — after all, every Web-filtering product vendor says so.)

Tribune won’t comment on Zell’s memo except to confirm that it’s authentic. But we know Zell has a law degree, so it’s safe to assume that he understands liability. Bandwidth and security issues aren’t his forte, but he appears to trust that his IT people are competent to manage the networks.

And productivity? Zell seems to think his employees are grown-up enough to get their work done, even with YouTube just a click away.

Or maybe he figures that in the age of the iPhone,…