What happened Shares of Criteo (NASDAQ: CRTO) gained 84.9% in February 2021, according to data from S&P Global Market Intelligence. The online advertising technology specialist rose thanks to a powerful combination of strong earnings and an ongoing strategy shift. So what Criteo's stock has been held down since 2017, when it became clear that the leading web browser makers wanted to get away from complicated privacy and security issues around third-party tracking cookies. Criteo and other ad-tracking experts have long relied on this technology to deliver highly targeted ad campaigns to their clients. Share prices rose more than 10% on Feb. 4 amid reports that Criteo would announce a business restructuring and a revamped system of ad tracking technologies. The company reported analyst-stumping fourth quarter results the next day, pushing stock prices another 24% higher. Besides beating Wall Street's earnings and revenue targets, Criteo also explained how a market-leading treasure trove of client relationships gives the company direct access to the browsing data that feeds the targeted advertising business. "This data is established through direct and privileged integrations with our retailer clients, enabling cookie-less targeting and retargeting across our commerce media ecosystem," said CEO Megan Clarken on the earnings call. Can someone help us target these ads? Image source: Getty Images. Now what Stocks that see their share prices nearly double in a single month often end up trading at nosebleed-worthy valuation ratios. Criteo is a different story. The stock looks downright cheap at 14 times free cash flows and 16 times forward earnings. The third-party cookie calamity that was supposed to doom this company turned out to be a paper tiger. Locking in my own Criteo profits at these prices would be a terrible mistake because there's a lot of growth left to explore in Criteo's corner of the digital advertising sector. 10 stocks we like better than CriteoWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and Criteo wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of February 24, 2021 Anders Bylund owns shares of Criteo. The Motley Fool recommends Criteo. The Motley Fool has a disclosure policy.Source