Other Sources of the "Slashdot Effect"?

mattsucks asks: "I was surfing Google News today, looking for something interesting. I had just loaded the page, and hit refresh. A new story popped up at the top of the news page, so I chased the link. 'Server Too Busy, Try Again Later' replied the kind webserver. Obviously a Google News-driven Slashdotting was in effect (pun intended). Another example: one of our local talk-radio DJs likes to have his listeners pound the web sites of anyone he is peeved at. He's the #1 DJ in his slot, so when he says 'click' he generates a LOT of traffic. What other causes have people found of the Slashdot Effect?"