Noun

1. A gravitationally domineering celestial body with an event horizon from which even light cannot escape; the most dense material in the universe, condensed into a singularity, usually formed by a collapsing massive star.
2. A sphere of influence into which or from which communication or similar activity is precluded.
   • 2006 October 23, Tom Zeller Jr., “The Internet Black Hole That Is North Korea”, The New York Times

     Julien Pain, head of the Internet desk at Reporters Without Borders, a Paris-based group which tracks censorship around the world, put it more bluntly. “It is by far the worst Internet black hole,” he said.

   • 2000 November 26, Linda Seebach, “Unwanted e-mail belongs in an Internet black hole”, RockyMountainNews.com http://rockymountainnews.com/seebach/1126seeba.shtml

     you'll have to love U.S. District Court Judge John Kane's decision to keep Denver-based Exactis.com out of an Internet black hole.... MAPS maintains a database of Internet addresses that it believes send or relay spam. It’s called the "Realtime Blackhole List"

3. An entity which consumes time or resources without demonstrable utility.
   • 2004 September 30, Andrew P. Leyden, “The Internet black hole”, PenguinSix, at PenguinSix.com http://penguinsix.com/?p=428

     Now that I’m basically up all night US Time, I’ve started to notice that there really isn’t that much going on on the net between say 10:00 and 9:00 AM EDT.

   • 2004 November 16, Jenifer Hanen, “How I fell down an Internet Black Hole....”, Black Phoebe, at www.blackphoebe.com http://www.blackphoebe.com/msjen/archives/2004/11/how_i_fell_down.html

     I finished some client work and gave myself 30 minutes to fall down one of my favorite internet black holes: genealogical research. Four hours plus some later, my eyes were burning in my head