As far as I can tell they're selling data. Their API requires hotlinking so they can track everything. They know exactly how often each picture is viewed and do

As far as I can tell they're selling data. Their API requires hotlinking so they can track everything. They know exactly how often each picture is viewed and downloaded. Unsplash knows which images are successful and which ones are duds. I'm not sure who they're selling to, but I'm sure lots of folks would be interested.