Why is the Media Obsessed with the Idea of Getting Fired for Blogging?

Tim Bray, Sun Microsystem's technology director asks a great question:

Uh, why is the mainstream press so incredibly interested in this people-fired-for-blogging story? Is this happening to a lot of people? No. Are a lot of people blogging? Yes. Has it happened to anyone senior enough to impact the company involved? No. Are senior people blogging? Yes. If I were cynical and paranoid, I’d suspect that the media running these stories were frightened of something.

It is a rather odd obsession... especially in light of Tim's list of 10 reasons why blogging is great for your career.