After Sunday night’s announcement that AOL is buying The Huffington Post for $315 million and giving Arianna Huffington editorial control over all of the media group’s content, let’s take a look at what everyone involved is getting out of this deal:

The Huffington Post: Money! Money and resources. As Arianna Huffington wrote in an e-mail to her site’s bloggers this morning (which I received—disclosure—because I used to be one), the buyout “makes it possible for us to execute our vision at light speed…it will be like stepping off a fast-moving train and onto a supersonic jet.” And as Huffington now has editorial control over all of AOL’s content producing sites, we assume that she will be able to incorporate content from Engadget, TechCrunch, PopEater, StyleList, etc. into her site, if she wants to add to the already-seizure-inducing crammed-full HuffPo homepage. The steady growth of the Patch.com network provides some interesting potential for Huffington Post to connect to local audiences, too. As for Moviefone and Mapquest, well…we don’t know what she’ll do with those duds, if anything.

AOL: America Online, the pioneer of dial-up that most people associate with chatrooms from the 90s, will try to borrow on the image of The Huffington Post, which, despite its SEO cheesiness, has still been able to maintain a certain hip factor since its founding in 2005. The Huffington Post has also established a huge readership, a readership that is incredibly involved in and engaged with the site. That’s a big audience for AOL to tap and try to sell crap to. Also: Labor! See the leaked memo that The Business Insider posted last week, detailing a truly depressing scheme at AOL to churn out more content, in less time, for less money, chosen almost entirely for its potential to deliver the most page views for the least amount of effort. Writers on staff at AOL, according to the memo, “are expected to write five to ten stories per day.” (That’s only the latest in AOL’s hiring and spending spree of late.) And what site has the most content produced for the least amount of money? The Huffington Post, which has managed to get a tidal wave of content—opinion, mostly, of course—for nothing at all. Which leads us to…

Writers: Huffington Post bloggers—and there are thousands of them—write for free because they get readers and perceived influence that they wouldn’t get otherwise just posting on their own personal sites. As Emily Bell, writing at The Guardian, puts it: “Huffington achieved a miracle for web publishing in 2005, by getting high-profile contributors to write for nothing, through a mixture of charm and brand association.” But will that last? Will bloggers be willing to keep on writing for nothing, with so much money now on the table? The coolness-factor of self-publishing on The Huffington Post diminishes over time, in proportion to how many more writers flood the site. And, speaking of that coolness, if AOL trades on HuffPo’s hip image, will AOL’s corporate image rub off on HuffPo? Besides the blogs, of course, The Huffington Post features a steady stream of aggregated content from elsewhere on the Web, and has also made some strides in investigative features. Original reporting, though, is still not yet a focus of the main site. Will that change with AOL entering the picture? And will AOL/HuffPo be able to use those millions to attract quality reporters and editors from elsewhere, emphasize original writing, and become a real player in the news game? The various new hires and layoffs that we see resulting from the merger will give us a better idea in the next few days and weeks.

News consumers: Salon’s Alex Pareene wrote today of the combined media entity, “This will now be the single largest SEO-gaming operation ever created.” Both AOL and the Huffington Post share the emphasis on click-happy headlines, which continue to clog up Google searches and make the original stuff harder to find. They also both emphasize speed over quality, aggregation over originality, and opinion over reporting. So perhaps this isn’t such an unlikely union, after all. And perhaps this won’t really change what online news readers are getting from what they’ve already got; they’ll just get it faster, and there will be even more of it.