http://slashdot.org/ is a community web site where contributors provide pointers to articles elsewhere on the internet, as well as opinions, flames, etc. on those articles. There are also frequently reviews of books, software, and general questions of discussion.
The term slashdot is sometimes used as a verb, as in "my site was slashdotted" - a term indicating that there were so many visitors that one's web site was unable to cope (or nearly so). Typically the term is used after one's site has been mentioned in the press or on some web site (most frequently slashdot ,)
If you want to gather the slashdot comments, see a little Slashdot comment parser.