The focus for the broad-based S&P 500 (^GSPC 0.70%) again turned to earnings today as weak top-line growth remained on center stage and upended what has been a steady stream of mixed economic data.

Trying its best to push the index to the upside was personal spending data and the final consumer sentiment reading for the month of January.

Personal spending for December, a key economic month for retailers since it includes holiday spending, rose 0.4% versus market expectations for a rise of just 0.2%. This would lead investors to the idea that retail sales figures for this holiday season may not be as bad as many economists have predicted.

Similarly, the final reading for January's Thomson Reuters/University of Michigan consumer sentiment reading rose to 81.2 from a preliminary reading of 80.4 earlier in the month, signaling that consumers are feeling slightly more confident about their short and long-term economic situations, as well as the economy as a whole.

Working against this data, however, was a weakened Chicago PMI and a higher employment cost index. The Chicago PMI, a measure of manufacturing activity in the Midwest, shrank to a reading of 59.6 in January (which by all indications still assumes healthy expansion) from 60.8 in December. Employee costs also rose 0.5% in December, compared to expectations for a 0.4% increase. Higher labor costs and slowing manufacturing sector expansion are two key ways to slow any stock rally down.

By day's end, the S&P 500 decided that weak revenue growth in select reporting companies outweighed this mixed data, pushing the iconic index lower by 11.60 points (-0.65%) to finish at 1,782.59, erasing a little more than half of yesterday's rebound.

Leading all companies to the upside today was renewable oils and bioproducts producer Solazyme (TVIA), which rocketed 32.8% higher after announcing that commercial operations for its algal oils have commenced at an Archer Daniels Midland (ADM -0.38%) facility and an American Natural Products facility, both in Iowa. The production, which is anticipated to hit 20,000 metric tons per year, could hit as high as 100,000 MT/year in subsequent years, according to Solazyme's press release. The initiation of commercial production has been a long time coming, so now it's time for the opinions to take a back seat and to see if Solzayme's concrete results in upcoming quarters can support its nearly $900 million valuation.

Struggling online social gaming developer Zynga (ZNGA) soared 23.6%, after announcing its fourth-quarter earnings results and undertaking a few surprise moves. For the quarter, revenue tumbled 43% to just $176.4 million, as bookings fell to $146.7 million and adjusted EBITDA dipped to $2.6 million from $45 million in the year-ago period. Cost-cutting, however, reduced its adjusted loss to $0.03 per share from $0.06 in the year-ago period. What has Wall Street excited is the announcement that Zynga will lay off 15% of its workforce in order to save $33 million-$35 million annually, and its $527 million purchase of NaturalMotion in order to expand its mobile offerings. The Street seems pretty content with Zynga's strategy of cutting internal costs and buying growth, but the online gaming industry is so fickle and competitive that Zynga still looks like a ship destined to sink -- at least in my view.

Finally, health care information technology provider Computer Programs & Systems (CPSI 2.76%) added 17.6% after announcing its fourth-quarter results and providing fiscal 2014 guidance. For the quarter, CPS delivered a 7% increase in revenue to $51.3 million as net income expanded modestly to $0.90 per share. These results were a bit mixed, as the Street expected only $0.84 in EPS but $1.5 million more in revenue. However, that was quickly forgotten as CPS' fiscal 2014 forecast called for $205 million-$215 million in revenue and $3.25-$3.40 in EPS. Current consensus estimates had only projected $2.99 in full-year EPS. This beat shows exactly how vital IT services have become to helping lower costs and improve efficiency in the health care industry, and gives me reason to believe that CPS could still have further upside potential.