SPY has had, as Eric said, a lot of technical damage today with some major trend lines being broken.
I am beginning to see how a "renewed belief in negatives" can take this thing over. There is a lot of black space to fall into with next support at 88-ish (sorry for the horizontal line.)
Low volume = complacency. And the next trade for many is to take some profits and I doubt many bulls will try to defend this beast once the noise machine starts up about increased regulation, poor consumer spending, increased savings rate and political unrest overseas.
The dollar is relatively oversold here and may make a bull run with any anxiety. TLT likewise is oversold. Most equity classes and commodities are overbought. You do the math.