This final note today, which I’ll kick off by mentioning that Facebook lost another 3.8 percent today. Just shy of $21 is what one share will cost you.

I mention that — and by implication Facebook’s completely messed up IPO — as a way to get to this item about the stock market. The New York Stock Exchange halted trading in a hundred or so stocks today after some really crazy volatility began showing up. It brought back memories of the flash crash of a couple of years ago.

No thousand-point drops or anything, but enough — when you wrap it in with the glitches around Facebook — to remind you that the markets most definitely aren’t perfect.