I have always liked the canary analogy. (Canaries were used in coal mines to identify harmful natural gas that could suffocate or explode. If your canary died, you had better get out!)
This story is about a GOP Guide to internet/blog/media interaction. Always assume the microphones are on, don't engage the hostile liberal blogs, always remember that a camera MIGHT be on when you do some stupid gesture. But the 'Blogs are your canary' comment was very apt.