Uncertainty with the conflicting reports today. Nonetheless, the lower inflation number does suggest that the Fed might cut rates next week as the economy is slowing down. The traders bought on that expectation. If they do not cut rates next week, the market will head lower and even if they cut rates, it probably will head lower because the economy IS slowing down.
Apple and Amazon report tomorrow after the market close and on Friday, the Jobs report comes out. If those are negative, the traders will begin selling on Friday.
Today was a lot of "taking advantage of the uncertainty",