AOL announced late Sunday that it has bought the Huffington Post for $315 million.

In a shocking post-Super Bowl announcement, AOL said tonight it has agreed to pay $315 million for the Huffington Post and form a new media powerhouse by combining the content of both organizations.

The resulting new outfit, which will be headed by HuffPo co-founder Arianna Huffington, will be called Huffington Post Media Group and feature all the content from previous AOL acquisitions including Engadget and TechCrunch. By doing so, AOL seems intent on convincing the world that it is deadly serious about reclaiming its place among the leaders of the digital media world.

In a story posted at midnight Eastern time, Huffington wrote that the new media group is expected to have a reach of 117 million Americans and 270 million people worldwide.

In addition to bringing together the HuffPo, Engadget, and TechCrunch, the move will also add other AOL properties including PopEater, Mapquest, Moviefone, and others. All told, the idea is clearly that the group will offer content aimed at the widest-possible range of readers: politics junkies, techies, housewives, car nuts, movie freaks, and more. By doing so, it will be well-positioned to take on the other leaders in the mainstream online media space, such as Gawker Media.

After becoming one of the largest players in the media world in the 1990s and then falling hard, a staggering roller coaster ride that crashed after its early 2000 ill-fated 12-figure purchase of Time Warner, AOL has been trying of late to resurrect its brand. In September, it purchased Michael Arrington's well-regarded and popular TechCrunch, and now, by buying the HuffPo and its claimed 25 million unique monthly visitors, AOL is stating loud and clear that it is back and demanding to be taken seriously.

The Huffington Post is one of the most-read online properties, and it is seen as a leader in politics, entertainment, women's issues, and much more. TechCrunch is a leader in tech business news, and Engadget is one of the most successful gadget blogs in the world. Now, AOL controls all three.

Though HuffPo has a sterling reputation among readers and a popular, high-profile figurehead in Arianna Huffington, it does not come without controversy. In its February issue, "Vanity Fair" magazine reported on a lawsuit filed by two Democratic Party insiders who claim they were uncompensated and unrecognized co-founders of the hit blog. In the article, Huffington refused to comment, but in court papers was said to have denied the merits of the suit.

In a statement late tonight, AOL and Huffington said she will become president and editor-in-chief of The Huffington Post Media Group. The deal is expected to become final late in the first quarter or early in the second quarter of 2011, the companies said.