He was previously a Senior Research Scientist at Yahoo Labs and Flickr, where his research focused on the visual and spatiotemporal dimensions of media, in order to better understand how people experience and explore the world, and how to better assist them with doing so. He led the development of the YFCC100M dataset released in 2014, and previously was part of the efforts leading to the creation of both MIRFLICKR datasets. He has furthermore been part of the organization of the ImageCLEF photo annotation tasks 2012–2013, the MediaEval placing tasks 2013–2016, and the ACM MM Yahoo-Flickr Grand Challenges 2015–2016. In addition, he has served on the program committees of, amongst others, ACM MM, ICMR, SIGIR, ICWSM and ECIR.