The web publishing practice, usually on news or blogging sites, where something controversial is written (or a controversial headling is written) that the publisher knows will get a lot of interest from site visitors.
The ultimate goal is that the link will then appear on link aggregating sites (Digg, Fark, StumbleUpon, College Humor, Drudge, etc.), which will bring even more traffic to the site.
"Hey, look at this! 'Gay Preacher Caught Having Sex With Porpoise!'"
"Hah, looks like link baiting to me."