What's happening: Shares of digital coupon marketplace RetailMeNot (NASDAQ:SALE) crashed on Wednesday following the company's second-quarter earnings report. RetailMeNot reported revenue of $53.2 million, down 11% year-over-year, and well short of analyst expectations. Non-GAAP EPS was $0.09, down from $0.21 during the second quarter of 2014, and five cents short of analyst estimates. At noon Wednesday, the stock was down around 32%.

Why it's happening: RetailMeNot is suffering from an over-dependence on the PC and search engines. Desktop online transaction revenue declined by 25% year over year during the quarter, falling to $38.6 million. This represents nearly three-quarters of the company's total revenue, and its decline overpowered growth in other areas. In-store and advertising revenue rose 72% year-over-year, while mobile transaction revenue increased by 91%, but combined, these represent just 27% of RetailMeNot's business.

CEO Cotter Cunningham summarized the company's main problem: "We continued to drive strong mobile, in-store and advertising revenue during the second quarter, but weakness in organic search, which began in late May, negatively affected both our desktop and mobile web traffic resulting in disappointing overall results."

Going forward, the company doesn't expect things to get better anytime soon. Revenue is expected to decline by 14% year over year during the third quarter, and for the full year, the company guided for an 11% revenue decline.

Investors are clearly not happy with the continued problems plaguing RetailMeNot's business. Prior to the earnings report, the stock traded at around three times sales and nearly 30 times earnings. With revenue now shrinking, it's no wonder that investors sent the stock tumbling.

Timothy Green has no position in any stocks mentioned. The Motley Fool recommends RetailMeNot. The Motley Fool owns shares of RetailMeNot. 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.