Yahoo has an actual yodeler, Wylie Gustafson. Credit: Yahoo. 

Shares of Yahoo! (NASDAQ:YHOO) were down slightly by 1 p.m Wednesday after the Internet giant Tuesday reported second-quarter earnings that fell short of Wall Street's projections:

YHOORevenueYOY GrowthEPSYOY Growth
Consensus estimate  $1,031.46 million (0.86%)   $0.19  (48.6%)
Q2 actual  $1,043.04 million  0.26%  $0.16   (56.8%)
DIFFERENCE  $11.58 million  1.12% ($0.03)  (8.2%)

Sources: S&P Capital IQ

Commenting on the results, CEO Marissa Mayer said in a press release: 

I'm extremely pleased with our achievements in Q2, with revenue growing 15% year-over-year, marking our most substantial GAAP revenue growth in almost 9 years. Our Mavens investment businesses across mobile, video, native and social grew to nearly $400 million in revenue this quarter, delivering 60% GAAP growth year-over-year. Further, our display business saw the most substantial revenue growth since 2010. Yahoo's transformation continues to make great progress.

What went right: Mobile and Mavens revenue showed strong gains. Mobile, in particular, jumped 54.6% year-over-year after a 61% surge in Q1, and now accounts for 22% of Yahoo's traffic-driven revenue. "Mavens" -- a loose acronym for mobile, native, video, and social -- brought in $399 million, a 60.2% increase over last year's Q2.

What went wrong: Display revenue is coming, but at a huge cost. Segment sales improved 15% year-over-year, but traffic acquisition costs tied to display inventory more than doubled over the same period. Companywide TAC more than quadrupled, turning last year's $38.4 million operating profit into a $44.8 million loss in this year's Q2, going by generally accepted accounting principles (GAAP).

What's next: Yahoo declined to provide third-quarter guidance in its press release. Analysts tracked by S&P Capital IQ nevertheless have the company generating $1,070.65 million in revenue and $0.20 a share in profit after accounting for stock-based compensation and other noncash items. That compares with $1,093.96 million and $0.52 a share in last year's Q3.

Longer term, analysts have Yahoo growing earnings by an average of 2.26% annually over the next three to five years. 

In the meantime, investors should continue to pay close attention to mobile metrics. More users engaging with the company's apps via mobile devices should lead to higher profits and improved cash flow.