There is also a simple summary in one of the comments:
Okay, if don't be stupid is too short and simple, how about "When you blog, think about reading the text out loud to your parents, your current and future bosses and colleagues, your friends, and your significant other."
Most of the tech heavy companies encourage their employees to blog, Google, Yahoo and Microsoft leading the way. Some Northrop Grumman employees from the shadows are also secret bloggers. A lot of start-ups maintain development blogs. In some cases it is free low-cost publicity and in other cases it might hinder the philosophy of security through obscurity.
Information is currency and needs to be carefully controlled, I paraphrase again from the Yahoo policy blog:
"....And realize that once a cat is out of the bag, you can never get the damned thing back in. The blog world is incredibly efficient at spreading rumors, secrets, rants, hyperbole, and your mistakes.
You'll make mistakes. We all do. Just try to be smart about it."
I need to keep this in mind when making every post.