The Simulcam and Fusion 3D camera inventions were not the only technologies that made James Cameron’s Sci-Fi epic Avatar a massive box office success. While smaller films have used social media to spread the word guerrilla-style, no other major blockbuster has employed a full-on social web marketing assault quite like Avatar.

The results in its case were a $232 million opening weekend, a total of one billion dollars in revenue by year’s end, and the rank of #2 highest grossing film of all time. Cameron’s $500 million act of hubris has paid off. Here’s an outline of the social media moves Avatar’s team made to achieve success.

Avatar has its own Facebook (Facebook), MySpace (MySpace), and Twitter (Twitter) pages. That’s getting to be standard these days. The 18,000-follower Twitter account has tellingly not been updated since a few days after the film’s theatrical release; once the word was out, the job was done. While it was active, though, its followers would retweet updates to their followers, who (if interested) would do the same, spreading the word all over the web. The Facebook Page is even more impressive, with over 700,000 fans.

Facebook’s updated Page features make it the place to be for brands seeking exposure. The site allows brands to push updates to fans. Those fans see the updates in their personal news feeds, and they can then share them with others, just like on Twitter. Avatar’s Facebook Page is also where the MTV-hosted live webcast was hosted — more on that later.

Granted, Avatar wasn’t the first film to take its trailer in a new direction for the web. It actually wasn’t first at any of these things, but an expansive strategy combining many of the best existing ideas was what made the film’s social media campaign a success.

It started out with something a lot of movies do now: an Apple trailer debut, announced on Twitter. Anticipation was high enough that the servers struggled to get the video out to everyone who wanted it. A second trailer rolled out a month later. The web trailers gained additional buzz when fans remixed them and mashed them up with other movies, something that the folks behind the Avatar marketing machine smartly didn’t interfere with.

It was yet another trailer that impressed us the most, though. An interactive trailer was presented as an Adobe Air (adobe AIR) application. It required a download, but it was worth it for Avatar fans. They could see featured content and they could read the latest social media updates about the movie from within the trailer. The stunt got press coverage and word-of-mouth buzz.