Well, the submitter of this article has a 5 year old account. They frequently submit news articles from a variety of sources, and are also an active commenter. (Though, they do seem to like posting quotes.)
The other two atlantic articles on the front page are from 2-3 year old accounts that likewise post a lot of pieces from various newspapers.
You're welcome to dig through their posting history for a conspiracy, but it's not jumping out at me.
Doesn't have to be new accounts. "Pay to post" is a regular occurrence and a lucrative side business for people on high-traffic, user-curated content sites like Reddit and Digg.
Hmm, you know, my comment defending the Atlantic posters actually does have a weird amount of upvotes. (Not a joke -- it's at +37 right now, which seems high given its placement and late timing in the thread.)
The other two atlantic articles on the front page are from 2-3 year old accounts that likewise post a lot of pieces from various newspapers.
You're welcome to dig through their posting history for a conspiracy, but it's not jumping out at me.