Stock futures started the day on a positive note, turning sharply higher in reaction to a wider-than-expected decline in August's producer price index (PPI) number. Despite thin volume during the morning hours, the major indices hovered in the black, awaiting the 2:15 interest-rate decision from Ben Bernanke and the Federal Open Market Committee.

Pleasantly surprising even the doves among us, the rate-setting board made an aggressive rate cut of 50 basis points to 4.75%. And ... they were off. Nearly all market sectors closed in positive territory, led by strong gains from the housing and financial-services groups (areas that have been most adversely affected by the recent credit crunch and subprime woes).

By the time the closing bell sounded, the Dow Jones Industrial Average (DJIA) had gained 336 points - the blue-chip index's biggest single-day jump in almost half a decade. With 29 of its 30 components closing above break-even - Boeing (NYSE: BA) was the lone exception - the Dow settled at 13,739.4, closing above the 13,700 level for the first time since July 25.

Elsewhere, the S&P 500 Index (SPX) tacked on 43 points, or 2.9%, to 1,519.78. Today marked the index's first close above the psychologically significant 1,500 threshold since July 25. And tech stocks weren't left out of the fun ... the Nasdaq Composite (COMP) rallied 70 points, or 2.7%, to 2,651.7, taking out the 2,650 mark for the first time since July 23. All three of the major market averages ended the session at their intraday highs.

Beth Gaston Moon is an analyst at Schaeffer's Investment Research.

DuPont (NYSE: DD) is mimicking the lead of the broader market today as it heads sharply lower. The main catalyst behind the stock's 5.5% pullback was its second-quarter earnings, which failed to match the consensus view on Wall Street.

In its latest reporting period, the chemical company said net income edged lower to $972 million from $975 million last year, with per-share earnings flat at $1.04, two cents below analysts' expectations.

Revenue was 6% higher at $7.88 billion, slightly higher than the $7.86 billion Wall Street was expecting. Sales outside the U.S. were particularly strong, with revenue in Europe jumped 12% higher; U.S. sales were up just 1%.

Looking to the future, DuPont reiterated that its full-year earnings should hit $3.15 per share (excluding items). This is three cents below analysts' expected $3.18 per share. In the second half, international growth is expected to aid the company, helping to offset rising ingredient costs and continued struggles in the U.S. housing sector. As CEO Charles O. Holliday Jr. told analysts in a conference call, "I'm not assuming anything improving in North American housing until well into 2008."

Should DuPont fail to pare its losses in afternoon trading, it will suffer the biggest single-day percentage decline since July 2005. A component of the Dow Jones Industrial Average, the company is currently contributing nearly 25 negative index points to the venerable blue-chip grouping.

Beth Gaston Moon is an analyst at Schaeffer's Investment Research.

I remember April 14, 2000. I was in my second year of business school, and it was only weeks before graduation; we were coasting to the end. I came out of my negotiations class and there was an almost visible buzz. Everyone was clustered around a TV monitor turned to CNBC. The NASDAQ was crashing, and the DJIA was dropping, 400 points, 500 points. It ended down 617 points, a record at the time, and with the terrific sell-off in tech stocks many of my classmates' day trading careers were coming to a terrible close. The mood was somber, indeed, and we all went home and clutched our already-confirmed job offers close to our hearts.

While the bear market continued for several years and many of my friends' dotcoms went under before they'd even found the best place to order pizza, somehow the ensuing months of depressed indices and falling averages felt more like the natural cycle of life; as if spring 2000 had been a huge earthquake and the next few years were aftershocks, mudslides, traffic jams. Difficult but not catastrophic. In the meantime, my portfolio stuffed with value picks was fine (but my dotcom, too, went bankrupt -- fortunately, several months after I quit, rendering my never-exercised options worthless).

Today, the market is down again. In lulls in meetings my colleagues check their Treos and report. Down 300. Down 400. As I finish a one-on-one confab, I hear: Down over 500 points. And I say, "it's not that big a deal." The DJIA was in record territory. A few months ago we whispered about record gains between meetings, we IM-ed each other with updates. Could it hit 12,000? It did, and kept on zooming up, up, record after record.

A 500-point drop today is nothing, not an earthquake from which to rebuild but more like a loud, spectacular thunderstorm that causes little damage. Full of sound and fury. Signifying: not much.