As both a blogger and a (once and future) political reporter, I can help Matt with this one: "I really do enjoy all the blogosphere in-jokes and so forth and would miss them if they went away, so maybe the only thing to do is educate, educate, educate. So have at it, what's an authoritative definition of "concern troll" we can offer up to Time's crack team of political reporters."
And it's only fitting that the answer comes from a place beloved by both bloggers and their nemeses in the press corps. Wikipedia. The hallowed common ground.
Here's the whole entry. It gives a solid definition, a relevant example, and advice on how to spot a concern troll when you're looking into its lying eyes.
"A concern troll is also a fictitious online identity whose proclaimed beliefs are not those its creator really believes and is trying to push.
The concern troll posts in web forums devoted to its declared point of view (for example, Democrats or fans of the Prius), and attempts to sway the group's actions or opinions while claiming to share their goals but with some "concerns".
For example, in 2006 a top staffer for Congressman Charlie Bass (R-NH) was caught posing as a "concerned" supporter of Bass's opponent Democrat Paul Hodes on several liberal NH blogs, using the pseudonyms "IndieNH" or "IndyNH." "IndyNH" was "concerned" that Democrats might just be wasting their time or money on Hodes, because Bass was unbeatable.
Suspicion of concern trolls is hard to verify without clearcut information about the IP number from which their posts originate, as there are people who naturally behave in such a manner.