Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

Barring a catastrophic and unprecedented market meltdown on New Year's Eve tomorrow, 2013 will end in the green for the stock market, which is finishing up one of its best years in more than a decade. The S&P 500 Index (SNPINDEX:^GSPC) is primed for its largest gain since the go-go market of 1997 as investors began putting skin in the game again. Many individuals are still devoid of any "skin" to put in the game, after the 2008-2009 financial crisis exposed asset bubbles and ravaged the average American's portfolio. Today the S&P lost just a fraction of a point, or less than 0.1%, to end at 1,841. 

The most severe decliner in the 500-stock index was Pioneer Natural Resources (NYSE:PXD), which saw its stock lose 3.1% as the price of oil fell below $100 a barrel. The sell-off, which came on lighter-than-average volume Monday, was barely felt by long-term investors who've watched the stock roar more than 70% higher in 2013. Pioneer Natural Resources accelerated its growth markedly this year -- after earning about $135 million in 2012, the business netted more than $500 million in the first three quarters already this year. 

Elsewhere, social media stocks weren't exactly the most popular investments going into the new year, as the fallout from Twitter's devastating downgrade on Friday brought down shares of Facebook (NASDAQ:FB) by 3.1%. Facebook is also losing influence with the younger crowd, while gaining traction with those 65 and older. This tendency, while not exactly quantifiable, definitely puts a damper on Facebook's "cool factor" with the very youth demographic that helped to popularize it. Facebook, after a botched IPO last year, has rebounded and now posts a $130 billion IPO, though with consumer tastes constantly shifting, one must consider whether that valuation seems bubbly.

Lastly, shares of the gold and copper miner Newmont Mining (NYSE:NEM) fell 2.8% Monday, as the world's most precious metal continued its slump. Finishing just $9 above its 52-week low, an ounce of gold finished trading at $1,203 today. Newmont Mining thrives when gold prices are high, but its biggest strength is also its biggest weakness, as years like 2013 inevitably send the stock tumbling. Newmont, which has lost half its value this year, is a pure gold play, and with gold suffering its worst sell-off since the early 1980s, faithful investors could do nothing but watch in horror. With the economy recovering and the Federal Reserve cutting back on its stimulus efforts, bets on gold will likely remain risky investments into 2014.

Fool contributor John Divine has no position in any stocks mentioned. The Motley Fool recommends Facebook and Twitter and owns shares of Facebook. 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.