The environmental consequences of shopping catalogs have
documented. For example, over eight million tons of trees are
consumed each year in the production of paper catalogs.
Now there is a website where you can go to opt out of them: catalogchoice.org.
(Note the .org, not .com)
They’ve been up for about a month, and have already stopped the
unwanted delivery of over 1.5 million catalogs.
Update: the origin of the project is explained here.