I personally started a position in SH this afternoon as the market took a turn lower to hedge some remaining long positions. Today certainly seems to have damaged the rally that began mid November 2012. It had to happen some time.
If you are paper trading GOOG, make sure you decide the level of volatility you are willing to accept. Get out now with some profit? Allow a slight dip below break even for support at the $785 level, or perhaps sell some now and wait to see if support holds? Others may even be willing to wait for a weekly chart tag of the 10 week moving average at around $700. It all depends on what you risk tolerance may be.
Check back later for a market review video.