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.

The Dow Jones Industrial Average (DJINDICES:^DJI) bounced back from a slow start today to finish nearly even, losing 21 points, or 0.1%, at the session's end. Concerns about Europe cooled off stocks this morning, sending the Dow down more than 100 points at one point. European indexes ended lower after the EU Commission said it expected unemployment in the single-currency zone to remain at 12.2% until 2015, when it's expected to fall to 11.8%. The eurozone economy is still expected to shrink this year, before growing in 2014, though some companies have seen improved results on the continent. Back at home, the ISM Services Index beat expectations with 55.4, against the consensus at 54.0, indicating that America appears to be getting stronger.

After hours, Tesla (NASDAQ:TSLA) shares were getting banged up as the carmaker disappointed investors with its fourth-quarter guidance. The electric-car juggernaut dropped 12% as it said it now expects to deliver 21,500 cars this year, down from previous projections of 25,000. Still, the quarter just passed was a strong one as the company beat earnings estimates of $0.09 with a $0.12-per-share profit and sales topped expectations as well. Today's stock drop must be viewed in the context of its meteoric rise this year, and even CEO Elon Musk said he thought the stock had been bid up too high.

Moving in the other direction was Pandora (NYSE:P), which jumped 9% after its October audience metrics showed that Apple's iTunes Radio had not stolen a significant amount of market share from the veteran Internet DJ. Pandora showed year-year-over growth in all categories, though the number of active listeners was down about 3% from September, likely defectors to iTunes Radio. While today's number seems to have proven that the competition hasn't killed Pandora, its growth has slowed significantly lately as it saw just an 18% increase in listener hours. We'll need another month's data to see if there's a continued effect on the growth rate. For now, Apple may not be a concern for Pandora as the company is still operating near breakeven with decelerating growth. Investors may want to bear that in mind.

Fool contributor Jeremy Bowman owns shares of Apple. The Motley Fool recommends Pandora Media. It recommends and owns shares of Apple and Tesla Motors. Try any of our Foolish newsletter services free for 30 days. We Fools may not 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.