Read Yahoo for a recap of what happened today.
My response: I think it is very hard to blame this whole thing on expectations for a slowdown in growth. There was a large market panic component (technical language: contagion) associated with the drop off. For example, it is very hard to explain a 200 point drop right at 3pm on market fundamentals. Rather, it is triggered by computers programmed to sell once the index falls below a certain level. Still, it makes for a headache heading into tomorrow.