It's dead, Jim.
Comet Elenin is no more.
According to both NASA and Sky and Telescope, Comet Elenin has disintegrated. A first-time comet, meaning it had never been into the inner Solary System before, Elenin was predicted by astronomers to be a bright, beautiful comet, if not quite in the same league as Hale-Bopp. It was simultaneously predicted by some (who didn't understand orbital mechanics) to be the end of the world. Instead, its falling inward toward the sun proved to be the end of the comet.
Coming in from outside the plane of the ecliptic, it would have made for a gorgeous sight for Northern Hemisphere observers, who haven't had a bright comet placed for good viewing in some time. The inclination of this comet relative to the ecliptic (plane of the solar system) would have changed that.
Instead, by April it was showing signs of coming apart at the seams. In August, it was hit broadside by a large coronal mass ejection from the sun, which blew away much of the volatile material that would have made it a lovely comet.
(Contrary to some claims, there was no "energy shield" which protected it from the CME. Any "sightings" of such a thing were likely inadvertent misinterpretations of a bow shock between the cometary material and the CME. Tetrahedral "shields" are unlikely in any event due to the difficulty in producing such a shape - spherical would be much more likely, IF such a shield had existed. I love the way the "true believers" shifted from "natural object" to "alien spacecraft" as soon as evidence for the former vanished in a puff of dust and gas.)
Three weeks before perihelion (closest approach to the Sun) which would have been on September 10, it completely disintegrated. According to comet expert John Bortle, "The decline/fade of Elenin was abrupt and dramatic."
All that's left of the once and never "planet-killer" is a loose, wispy cloud of gas and dust, rapidly dispersing, according to photographs.
Hopefully, so too will be the rumors of its threat.