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 S&P 500 Index (^GSPC -0.22%) gained ground for a second straight day on the heels of poor housing data. Usually poor housing data would drive the market lower, but the 13% drop in single-family home sales in July sparked hopes that the Federal Reserve may not begin tapering its asset purchase program next month. The index added 6 points Friday, or 0.4%, to end at 1,663. 

Unfortunately, the weak housing numbers weren't such good news for homebuilder DR Horton (DHI 0.10%), which shed 2.9%. The drop in new home sales was the most severe monthly decline in more than three years, as the real estate market pulled back more suddenly than most analysts were calling for. Although interest rates didn't escalate Friday, higher rates have been another plague on homebuilders like DR Horton recently. 

Data storage company Western Digital (WDC -2.64%) lost 2.8% Friday, despite little bearish news of the sort DR Horton received today. Investors may simply be taking some chips off the table after a run-up that's seen shares advance more than 50% in 2013 alone. The landscape of data storage is certainly an area to keep a close eye on -- especially for Western Digital shareholders -- as cloud computing and deep data diving and analysis continue to be areas of big growth going forward. 

Finally, software giant Oracle (ORCL -2.25%) shed 1.9% Friday, as its bitter rival Microsoft shot higher on the news that CEO Steve Ballmer is set to leave the company within the next year. What's good for Microsoft isn't always bad for Oracle, but that's certainly what the market seemed to be saying today. Aside from the shakeup at Microsoft, investors have to worry about Oracle's business itself, which has whiffed on software sales expectations the last two quarters.