Beau Monday has some comments on the nature of courage. In his notes, he basically equates courage with physical risk. I agree that physical risk is often present at acts of courage – but I think that it is the RISK, not the PHYSICAL part, that makes it courageous. Even if the risk is only in your head, defying that risk for others is courageous. Overcoming a deep-seated fear can be courageous.
Having said that, I agree with Beau on his specific example – if Wil Wheaton thinks he is taking a big risk by putting his political opinions on his blog, he’s got an odd sense of risk. (Now, if he lived in a culturally repressive country and did this, that would be courage…)