Because many local markets lack centralized "Multiple Listing Services" (MLS) like those in the US, searching through "Oglasi" is the only way for buyers to see the full breadth of the market.
The largest "Oglasnik" (classifieds site) in Croatia. It is the primary destination for real estate, motor vehicles, and general consumer goods.
In the Balkans, the term "Oglas" is synonymous with a few dominant digital marketplaces where individuals and businesses buy and sell everything from real estate to services.