Upworthy launched in March; 2.5 million uniques in July, 4 million in August, 6 million in September.

They have 13 curators and unlike unbiased BuzzFeed they have a very liberal agenda.

Their mission is to find viral content on important topics.

Upworthy isn’t the only new news site that seems to be growing quickly:

In tech, The Verge is another. But Upworthy is growing faster than the growth in recent years of media start-ups like the Huffington Post, BuzzFeed, Business Insider and Mediaite, none of which had six million uniques a year after launch.

For Patrick Chung — who said he was brought into the deal by his friend Chris Hughes — his investment in Upworthy has a bit of a moral tinge to it. “The general level of mass discourse in this country is not very impressive,” he told AllThingsD. “When you have a platform as powerful as what we’ve invented (a.k.a. the Internet), it is a crying shame when it’s used for cat videos.”

“If I see another social media photo-sharing site I will scream,” Chung said, “but this is so different. It’s so optimistic; it’s the triumph of quality.”

Chung added that he wasn’t particularly worried about a business model for Upworthy, with multiple options available given the audience it has amassed. NEA is carving out a bit of a new media category along with other investments in BuzzFeed, SAY Media and Punch Media.

So what’s next for Upworthy? The 13-person company, which has a distributed staff of “curators” and product folks, is interested in creating and giving a platform to more original stuff. As Pariser put it, “We’re good at writing good headlines, but that’s a different skill than putting together great longform content.”

Another media company going into longform?!

Last week Tumblr announced they're going into longform, too.

I believe the opposite -- that short form is the future.

Not all the content is political.

Most of the biggest hits are videos.

The biggest hit is a video of a woman who owns how fat she is.

That got four million views.

Second biggest hit is a video of Mitt Romney being uncomfortable around a gay veteran.

That got two million views.

Is Upworthy hit-driven? No, they're doing something bigger.

This content has mostly spread through the Dark Social.

Only recently has Facebook become a channel for them, and Twitter has been mostly useless for Upworthy because Twitter people only want to talk about Twitter.

Growth Hack: Support content that people WANT to spread and they'll share it naturally by email, IM, etc.