The most popular genre of YouTube videos these days is, not surprisingly, trailers for summer and autumn Hollywood blockbusters, (usually the kind involving the imminent invasion of Earth or some other kind of sci-fi menace). The trailers for Transformers 2 and 2012 alone have amassed more than 9 million viewings so far. The competition for eyeballs is so fierce that Paramount Pictures has even decided to start plugging now the release of its big summer sci-fi adventure flick The Last Airbender, a full year ahead of its big-screen debut. Too soon? You be the judge.

Stats: Paramount posted this video on June 22, registering more than 237,000 viewings and nearly 2,300 text comments in the first four days. Other fans of the Last Airbender story have posted their own "teaser" vids, bringing the total number of viewers closer to 1 million.

What you see: "He is the last of his kind, all that remains of a once powerful nation," the solemn voice-over informs us, while in a ring appears a robed samurai busting some impressive moves. Cue ominous music as the narrator informs us some unnamed baddies are bent on destroying this young shaven-head hero. The camera pulls back, and the perspective shifts to the sea where a menacing armada bombards the screen with flaming artillery.

Takeout/take-away: The official big-screen debut for The Last Airbender in the United States is not until Independence Day weekend, 2010. But Hollywood is a firm believer in the axiom: It's never too early to start building buzz. It doesn't even matter if the crew is still in post-production, evidently.

Social-media effect: Producers of sci-fi adventure flicks have to feed the YouTube beast well before the final edits are made. That much is beyond dispute. But at some point you'd wonder if teaser trailers posted online a full 13 months before the movie hits theaters is a good strategy? How do you keep interest high then over the long autumn, winter, and spring? By producing trailer after trailer? Hollywood will watch this strategy closely to see at what point trailer fatigue sets in or whether it needs to build interest even earlier in its expensive summer blockbusters.