It's Shark Week! Have you heard? Discovery Channel's annual week of shark-themed programming began last night, back for its 23rd year of scaring people away from the beach. Buzz surrounding the line-up is inordinately high for what amounts to a week of nature programming. Sure, it's six nights of awesome, horrifying, brutal shark attacks. But it's also the 23rd year of six nights of awesome, horrifying, brutal shark attacks. Sharks haven't really changed the way they eat people in the past two decades, so why has Shark Week only gotten more popular over the years? Newsweek ventures a guess:

Because appreciations are the currency of small cable channels (see also: The Weather Channel's love of all things storm related). Shark Week is, on its face, a truly genuine admiration of the majesty of "nature's perfect killing machine." But frankly, if you've watched five minutes of the ballyhooed event, you've seen the whole thing. Four of the six Shark Week specials airing this year include references to shark teeth in their titles, and the other two are also about attacks--they just have more boring names (Shark Attack Survival Guide and Day of the Shark 3). That fact that this year's Day of the Shark is a three-quel, by the way, should give you a clue as to how little the programming varies year to year.

So why do viewers keep coming back? For one thing, Shark Week helps galvanize environmental-rights groups, which see the TV event as a chance to shed light on the difficulties faced by sharks in the wild: more than 100 million sharks are killed around the world each year by commercial fishing. Sen. John Kerry has even sponsored a "Shark Week bill" (the Shark Conservation Act of 2009) to help curb shark finning. What's even more remarkable is that Shark Week actually unites both sides of the eco-divide: the tree huggers who want to save every minnow in the sea, and the red-state good ol' boys who like to watch things get smashed to smithereens just for the heck of it. The bilateral appeal of watching sharks in their natural habitat translates into a big ratings booster for the Discovery Channel; Discovery Communications experienced a 2 percent "Shark Week bump" in shares today. There's a bit of a chicken-and-egg problem here: does the Discovery Channel promote Shark Week mercilessly because it's the only thing that gets people psyched about the Discovery Channel, or is the show successful because of how cleverly it is marketed?

Read the full story at Newsweek.