What happened

Shares of QuinStreet (NASDAQ:QNST) are trading 18.4% higher here at 3:20 p.m. EDT, following the online marketing specialist's first-quarter earnings report.

So what

QuinStreet's third-quarter revenue rose 29% year over year to $113 million, nearly doubling the bottom line from $0.08 to $0.14 per diluted share. The Street consensus had been pointing to earnings near $0.13 per share on sales in the neighborhood of $103 million.

Encouraged by this quarter's solid results, management also raised their full-year revenue target. Fiscal-year 2019 is now expected to see between 15% and 20% revenue growth, up from an earlier 10% guidance marker.

A man holding up a white posterboard with the words Digital Marketing in the middle and arrows pointing to various related keywords such as Like, Internet, SEO, and Followers.

Image source: Getty Images.

Now what

The company enjoyed double-digit sales growth in all of its reported client categories, paired with widening profit margins to generate even faster-growing earnings. QuinStreet's focus on digital and online marketing campaigns serves it well as clients move larger and larger portions of their advertising budgets off of old-school alternatives such as billboards and print ads and into QuinStreet's wheelhouse.

In particular, the all-important financial services sector delivered 32% year-over-year revenue growth and represented 69% of QuinStreet's total sales. Within that segment, management saw strong demand for insurance campaigns but a softer mortgage market.

Including today's big jump, QuinStreet's shares have crushed the broader market with an 86% gain over 52 weeks. The stock still looks relatively cheap at 16 times forward earnings, especially in light of these fantastic growth trends.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.