"For those of you who don’t know, The Black List is an annual list of Hollywood’s most liked unproduced screenplays. It started in 2004 when Franklin Leonard, a development executive for Appian Way, asked folks in the business to send in their list of top 10 unproduced screenplays. Those lists were complied into The Black List (which now as a site entirely devoted to The Black List).
Previous Black List scripts include “The Queen” , “Little Miss Sunshine” and “Juno”.
http://www.simplyscripts.com/2009/12/13/the-black-list-2009/
Translation: A dude who reviews scripts for a living started talking to other people who had the same type of job and created a list of which scripts were the most interesting that currently were not attached to a studio and currently did not have any plans of being made.
The list was published annoymously once a year for a few years until somebody blew the whistle and made the author's identity public.
The list continued for a few more years until the author decided to make a living at it and changed the list into an ongoing database and website that gives the same kind of rating to all unproduced scripts. You can sign up for an account on their new site (for a fee) and access their database of unproduced scripts and see what the interest level is for each script.
Site (link)