The Demand measure followed by the Trading Psychology Weblog is an index of the number of stocks displaying significant momentum (bullish/bearish) on a short- and intermediate-term basis. After Thursday's rise on the heels of the Fed news, we had the strongest Demand to Supply reading since the bull market began in late 2002.
When Demand has been extraordinarily high (over 160; N = 12) since October, 2002 (N = 942), the market (SPY) has been up by an average of .78% four days later (11 up, 1 down)--much stronger than the average four-day gain of .16% (518 up, 424 down) for the entire sample.
This fits well with my prior research, which suggests that strong and broad upmoves tend to persist in the near term.