OLX's seller ratings looked like verified reviews — the algorithm polished them. PLN 28.4M

On OLX.pl, Poland's biggest classifieds marketplace, a seller's rating decided who got the sale. But the ratings were not what they looked like. Users could rate a seller after merely asking about an item or viewing contact details — no purchase needed — while the display suggested reviews from verified buyers. And users could not rate freely: the platform sent one invitation per week, covering only the most recent experience, so earlier transactions went unrated unless the newest one was rated first. Dismiss the push notification in the app and the chance vanished entirely.

The algorithm did the rest. It converted a three-level input — great, good, bad — into a four-level display, weighted positive reviews more heavily than negative ones, and reclassified scores below the midpoint as positive: a seller with more negative than positive reviews could still appear as 'okay'. Consumers had no way to check whether the aggregate score matched the reviews behind it.

On 12 June 2025 UOKiK fined Grupa OLX 28,420,869 zloty (decision DOZIK-2/2025) for unfair market practices infringing collective consumer interests; the practices ran from November 2020 to 31 July 2024, when the platform replaced the system with arithmetic-mean scoring limited to verified purchases sent via OLX Shipping. Research commissioned by UOKiK found 86% of online shoppers treat reviews as crucial. A separate proceeding examines misleading information OLX supplied during the investigation.