So far in 2013, the stock market has responded optimistically to news of an improving economy and better prospects for the future. Yet more recently, the Dow Jones Industrials (DJINDICES:^DJI) have been stuck in a tight range around the 14,000 level, moving back and forth across the milestone as investors weigh the chances that stocks need to put in a correction before challenging all-time high levels for the Dow and the S&P 500. That tug-of-war ended in a modest decline today, with the Dow falling 36 points even as the S&P and Nasdaq managed to advance slightly.

General Electric's advance from the buyout of its stake in NBC Universal helped boost the Dow, but it wasn't the only gainer in the average. Alcoa (NYSE:AA) also gained the better part of 1%, similarly indicating that strength among industrial-oriented companies could well lead the overall market higher. The aluminum giant hasn't turned the corner yet, as European economic woes and a sluggish recovery in emerging markets have held back global industrial activity from getting back to its former peak, but when it does, Alcoa stands to gain from its timely moves to take advantage of weaker players in the industry.

Elsewhere, Trulia (NYSE:TRLA) jumped almost 22% after reporting strong fourth-quarter earnings. The newly public real-estate website company called out mobile growth in particular as driving the better-than-expected results, and even though the company posted a small loss, improved guidance on current-quarter revenue was particularly exciting for bulls. In a sign that Trulia's results were seen as indicative of industrywide strength rather than particular success for the company specifically, rival Zillow (NASDAQ:ZG) climbed 8% as investors apparently believe that it, too, will benefit from greater mobile traffic in real estate.

Finally, battered social-media deal company Groupon (NASDAQ:GRPN) clawed back some ground today, rising 5% as the stock got an upgrade from Sterne Agee. The analyst firm believes that between a strong mobile position and the company's ability to move beyond its original business model to expand both within the U.S. and internationally, Groupon should be able to take its initial pre-IPO success and move forward with new growth initiatives.

Fool contributor Dan Caplinger has no position in any stocks mentioned. You can follow him on Twitter: @DanCaplinger. The Motley Fool recommends Zillow and owns shares of General Electric and Zillow. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.