There are some people who feel it their God-mandated duty to attack unelected persons on their blogs for whatever reasons. I, as a rule, am not one of those kind of people.
There is a good reason for it; and it is found here on Opposing Views:
A climate scientist widely known for his “hockey stick” graph showing a steep climb in global temperature over the last century, can go ahead and sue two right-wing blogs for libel, a judge ruled last week.
The blogs compared the scientist, Michael E. Mann (pictured), to convicted child molester Jerry Sandusky. Mann teaches at Penn State University where Sandusky was a top assistant football coach under coaching legend Joe Paterno.
The case stems from two separate blog posts that ran in July of 2012. The first appeared on the web site OpenMarket.org and was then quoted approvingly at length in the online version of the conservative magazine National Review.
Both posts referenced a supposed scandal that conservative media labeled “Climategate.” The scandal involved a series of e-mails stolen by hackers off various university computers that were said to reveal prominent climate scientists discussing how to cover up data that contradicted their theory of global warming.[…]
Mann sued both The Chronicle and National Review, saying that the publications had defamed him and damaged his reputation. The publications filed motions to dismiss the lawsuit, which were heard by Washington D.C. Superior Court Judge Natalia Combs Greene last week.[….]
Greene ruled that Mann’s claims can go forward. She added that Mann’s case was likely to succeed “on the merits.”
“Plaintiff is a member of the scholarly academy and it is obvious that allegations of fraud could lead to the demise of his profession and tarnish his character and standing in the community,” the judge wrote.
Again, this is why I do not attack people who are not elected officials. I have personally been slandered in the liberal and Conservative blogosphere both. If I did have the funds to hire a lawyer and sue those who have slandered me, I would absolutely do so. As a rule on this blog; I write in respectful, (usually) terms my disagreements with the political ideologies of the progressive world. 
As the President has correctly stated in the past; that words matter and this case, the words of someone who decided to attack this man, because they happened to disagree with his opinion; is going to cost someone a good deal of money. So, in this writers opinion, it pays to be very careful. Believe me, I know all about what happens, when one gets reckless with his words. 
Update: Others: The Moderate Voice