What is the Commons Worth?: Estimating the Value of Wikimedia Imagery by Observing Downstream Use

The Wikimedia Commons (WC) is a peer-produced repository of freely licensed images, videos, sounds and interactive media, containing more than 45 million files. This paper attempts to quantify the societal value of the WC by tracking the downstream use of images found on the platform. We take a random sample of 10,000 images from WC and apply an automated reverse-image search to each, recording when and where they are used 'in the wild'. We detect 54,758 downstream uses of the initial sample and we characterise these at the level of generic and country-code top-level domains (TLDs). We analyse the impact of specific variables on the odds that an image is used. The random sampling technique enables us to estimate overall value of all images contained on the platform. Drawing on the method employed by Heald et al (2015), we find a potential contribution of USD $28.9 billion from downstream use of Wikimedia Commons images over the lifetime of the project.