Ask HN: What's the new Slashdotting?

Back in the olden dayes, the unit of flood demand was a Slashdotting [1]. If you wanted to make sure your site stayed up under a sudden flood of interest, you figured out what a Slashdotting looked like, simulated that, and you were probably good. Later my yardstick was "an Oprah". I had good data on what it looked like when Oprah mentioned your site on her show, so I would build for that. But that's getting a little dated.

So: what level of traffic do HNers simulate to test what a flood of public interest looks like?

Big bonus points for hard data from actual flash crowds.

[1] http://en.wikipedia.org/wiki/Slashdotting