You make a good point. I did a little digging through my webhost's forums: inconclusive on the question of exactly what would happen to a shared account if the owner's site was hit heavily enough. The vibe I got was that being throttled or taken offline would not be out of the question, although it seems like they are better prepared than most for dealing with the effects of a "full frontal slashdot" (i.e. front page slashdot on a shared account).