Here's a quick Pepper plugin called Holy Crap! I wrote for Shaun Inman's Mint software. The idea is simple: it sends you an email alert whenever it detects your site has become popular on del.icio.us, Digg, etc. Think of it as an early warning system.
It's easy to add your own warnings to the Pepper. Out of the box it looks for traffic coming from the popular site lists on
Why the name Holy Crap!? Because that's generally the first thing you say when your website hits the front page of Slashdot.
I just finished writing it earlier this afternoon, so I haven't given it a super-thorough testing just yet. But it appears to be working ok so far. Still, send in any bugs you find.