Four days, four straight losses. Equity investors have had a rough go of it over the past few days. Today was more of the same. Investors were left out in the cold as they looked to the European Central Bank for strong signals or -- perish the thought -- even action to counter the currency bloc's years-long debt crisis. European Central Bank President Mario Draghi pledged to explore unconventional options to preserve the tenuous currency union, but he came up short on specifics.

Investors were not pleased.

European markets at the center of the crisis plummeted. Spanish and Italian stock markets declined 5.2% and 4.6%, respectively, on the day. Across the Atlantic, U.S. stock indexes fared reasonably better. The Dow Jones Industrial Average (INDEX: ^DJI) shed 0.7% on the weak ECB news. Similarly, the S&P 500 and Nasdaq both lost ground by 0.7% and 0.4%. On a day where investors were clearly on edge, the market's so-called "fear index," the VIX (INDEX: ^VIX), took a breather. After spiking into positive territory around midday, it went on to post a surprise 7.3% decline during the day's trading.

Around the markets
Today's trading action saw its fair share of massive price swings. Shares of market pinata Green Mountain Coffee Roasters (Nasdaq: GMCR) surged 24% after announcing quarterly earnings. Despite missing on most key metrics, investors were enthused by management language about better ways to track K-Cup purchases and about a new $500 million share-buyback program. Color me skeptical. The company faces a litany of issues, ranging from questionable accounting practices to upcoming patent cliffs.

On a more substantive note, shares of local business-media site Yelp (Nasdaq: YELP) also soared today as the company reported impressive quarterly results. The company grew revenue 67% last quarter and posted a better-than-expected net loss. Although the company does rely on an advertising-based business model, which I'm typically skeptical of, the report today was undeniably impressive. In keeping with recent IPOs, shares of social-networking giant Facebook (Nasdaq: FB) tumbled another 4% today, marking its lowest closing price since the company made its public debut. The company released figures today estimating that approximately 4.8% of its monthly users were duplicate accounts.

Foolish bottom line
At the end of the day, single-day market swings matter very little. While it's crucial to stay up to date on the goings-on with your holdings, concentrating on finding and buying stocks with the makings of long-term winners more often than not generates a more favorable outcome. The Fool recently identified three Dow stocks that have all the makings of longtime winners in a research note, which you can access for free.