Who's hiding under the bridge of an online science article?

Trolls, that's who.  Discovery News gets first crack at discussing them in Scientists VS Internet Trolls!

Scientists on the cutting edge vs pessimistic web trolls! All across the Internet, scientists are forced to continually defend their work against a group of people discounting their research. What's so controversial about their work, and why the attention? Trace puts a spotlight on all the haters and gets some answers!

Trace at DNews at least can put a positive spin on the critics in the comments. At least some of them are genuine skeptics who are open to persuasion and reason, while others are just, well, trolls.

On the other hand, Chris Mooney at Mother Jones describes a more malignant type inhabiting the comments section of climate blogs in The Science of Why Comment Trolls Suck.
The online peanut gallery can get you so riled up that your ability to reason goes out the window, a new study finds.
Thu Jan. 10, 2013 3:06 AM PST

Everybody who's written or blogged about climate change on a prominent website (or, even worse, spoken about it on YouTube) knows the drill. Shortly after you post, the menagerie of trolls arrives. They're predominantly climate deniers, and they start in immediately arguing over the content and attacking the science-sometimes by slinging insults and even occasional obscenities. To cite a recent example:

What part of "we haven't warmed any in 16 years" don't you understand? Heh. "Cherry-picking" as defined by you alarmists: any time period selected containing data that refutes your hysterical hypothesis. Can be any length of time from 4 billion years to one hour. Fuck off, little man!?

It was reasonably obvious already that these folks were doing nothing good for the public's understanding of the science of climate change (to say nothing of their own comprehension). But now there's actual evidence to back this idea up.

As someone who has been recognized for excellence in trolling three times, these people aren't really trolls.  These people are mission posters.  If they're paid, and some of them are, they're Agents.

Agent is a sinister and elusive opponent who usually works in concert with other Agents. Agent generally uses standard combat techniques, but differs from other Warriors in that he is in the employ of some organization. The organization may be political, commercial, or even criminal, and it’s Agent’s job to post messages that advance his employer’s interests.

I get my share of Agents here, but they're just spammers.  A denialist would actually be a step up.