Challenge is a meta-search platform that gives detailed information to travellers about vacation regions and hotels of Turkey. It is the only platform of its kind in Turkey thanks to its rich hotel portfolio, unbiased comments, and big partner operators. provides call forwarding and traffic redirection for the hotels, OTAs and travel agencies they work with, so convincing visitors to call hotels for direct booking is a major factor in their success. As such, their challenge was to reach the most relevant audience possible.


To increase their conversion rate and reach a highly engaged audience, used Criteo Dynamic Retargeting to serve personalized ads on a broad range of publisher sites. With Criteo’s unparalleled reach, connected with users wherever they were, across the web, devices, and apps. A deep understanding of each shopper, fueled by Criteo Shopper Graph, the world’s largest open shopper data set, ensured that they targeted those most likely to convert with the most engaging offer. And Criteo’s proprietary dynamic creative optimization technology ensured that each ad was tailored based on each shopper’s preferences.

How it works:

  • Highly personalized ads showed products that a shopper was most likely to be interested in, when they were most likely to buy.
  • Ads were focused on those who were most likely to convert by accurately predicting purchase intent, using an anonymous cross-device understanding of each shopper’s behavior across all devices, browsers and apps.
  • Ads seamlessly connected with every shopper across devices, apps, and the web through insights from our pooled data and the 1.2 billion shoppers we see each month.
  • Campaigns were continuously optimized to remove ineffective placements and focus on high-potential shoppers based on conversions, not just clicks.


  • +339% increase in overall onsite conversions QoQ
  • 60% of conversions came from Criteo’s Product Recommendation Engine
  • +10% increase in conversion rate
  • 4x increase on phone call lead conversion rate

“Criteo has scaled our success with profitable CPO and positive ROAS rates.”

–Çağdaş Polat, CMO,


Increase in overall onsite conversions QoQ


Of conversions came from Criteo’s Product Recommendation Engine


Increase in Conversion Rate


Increase on phone call lead Conversion Rate