I found this as I was catching up on my RSS feeds this morning. Dan Shawbel of Mashable! has an awesome post about how "Personal Branding Can Save You From Getting Fired."

I talked about this in my presentation to Regina Cassell's class a
couple weeks ago. By establishing a web presence (that you keep
updated) that promotes yourself as an expert on a given topic, your
marketability (and job security) is enhanced.

Shawbel makes several other points that are worth your time. Really,