You could trace the roots of Blackest Night to a whole lot of places. Obviously, there's Green Lantern: Rebirth and Sinestro Corps War, Geoff Johns's two previous epics that both laid important groundwork for what's going to play out over the next eight months. There's also "Tygers", Alan Moore's 1986 story from Tales of the Green Lantern Corps Annual #2, which prophesied much of what Geoff Johns brought to pass in Sinestro Corps War and has provided (with some minor revisions) one of Blackest Night's major antagonists. But, for my money, all of this really goes back to the death of Superman.
1992's yearlong saga of Superman's death and ultimate return had one rather obvious effect on the world of Green Lantern, as the villainous Cyborg Superman destroyed Hal Jordan's native Coast City as part of the original Mongul's plan to turn Earth into the new Warworld. That tragedy was the impetus for Hal Jordan's descent into madness and villainy, as he assumed the new identity Parallax. To make a long story short, Parallax wiped out the entire Green Lantern Corps and all but one of the Guardians, tried to rewrite time in Zero Hour, operated as a villain for a while, heroically sacrificed himself by reigniting the sun in Final Night, languished in purgatory, and then became the new host for the Spectre, God's Spirit of Vengeance, which he tried to reinterpret as a Spirit of Redemption.
Whatever the artistic merit of any of these decisions, they were widely reviled by fans of Hal Jordan, and Green Lantern: Rebirth sought to undo the damage with one of the more audacious retcons in comics history (which, considering the audacity of your average comic book retcon, is really saying something). It turned out that Hal Jordan had been possessed for years by the cosmic embodiment of fear, a yellow entity known as Parallax. It had taken Parallax years to burrow its way into Jordan's consciousness - even his stress-induced graying temples were pointed to as evidence of the internal struggle - and the destruction of Coast City was what finally allowed it to take hold.
Beyond providing a just about reasonable way to get Hal Jordan off the hook for some pretty unforgivable crimes, the introduction of Parallax also recast the larger cosmology of the Green Lantern mythos. Previously, yellow had simply been a color against which Green Lantern rings did not work. Sinestro, Hal Jordan's former mentor turned mortal enemy, was given a yellow power ring after his expulsion from the Green Lantern Corps, but this ring had been unique, a gift from the anti-matter universe Weaponers of Qward. Now, yellow was the color of fear just as green was the color of willpower, and Sinestro's ring was the basis for an entire corps.
The bloody, brutal war between the Green Lantern and Sinestro Corps was terrible enough in its own right, but its specific events suggested far worse was to come. Alan Moore's 1986 story "Tygers" featured Hal Jordan's predecessor Abin Sur traveling to the hellish prison planet Ysmault, where he learned of the future of the Green Lantern Corps from the demoic Qull of the Five Inversions. What Qull foretold in "Tygers" came to pass in Sinestro Corps War, although the Green Lanterns escaped what was supposed to be their ultimate destruction. However, it's recently been revealed that Abin Sur returned to the planet several times, attempting to learn more of the Corps's future.
He eventually learned of the prophecy of the Blackest Night, which concerned a chaotic War of Light between several different Corps that would leave the universe too badly fractured to defend against the coming of the Blackest Night. The Guardians of the Universe have attempted to prevent this from coming to pass by enacting a number of new laws for Green Lanterns to follow. These new rules, which include enabling lethal force and forbidding romantic entanglements between Green Lanterns, have seemingly had the opposite effect, sowing discord and distrust between the Guardians and some of their most trusted Lanterns. And, for all their efforts, all the other Corps have come into existence, each with their own agendas and their own roles to play, which is discussed here. It looks like the final prophecy is coming to pass after all.
That's the long road connecting the Death of Superman and Blackest Night, but there's something much more basic at work here. Superman's revival was just the first of many, many resurrections in the DC universe, something that has been much criticized. Several writers have actually sought to address this, if only obliquely, by suggesting Superman's miraculous return broke down part of the boundary between life and death, enabling what has become a revolving door of resurrected heroes. Green Lantern #43, last week's prologue for Blackest Night, suggests the driving force behind the Black Lantern Corps is Death itself, and it wants its escapees back. (So yes, the premise of Blackest Night is essentially that of Final Destination, except the protagonists are cosmic warriors instead of stupid teenagers and Death will use undead superheroes instead of ridiculously circuitous, carefully choreographed accidents. I'd say that's a trade up.)
DC Executive Editor Dan Didio has suggested Blackest Night will close the door on death as a device in the DC universe, with characters mostly either remaining alive or staying dead after all of this plays out. Retiring these admitted overused devices - the "shocking" death and the inevitable resurrection - is a laudable goal, if only because both have completely lost their impact. It's hard to say whether DC is actually going to be able to stick to this goal, but just the statement itself makes it clear that, much as Infinite Crisis had the secondary purpose of resolving some of the DC universe's worst continuity problems, Blackest Night will seek to resolve how so many characters, beginning with Superman sixteen years ago, have so routinely been doing the impossible and coming back to life.