Public user profile information is a common feature of modern websites. These profiles can provide a valuable resource for investigators tracing digital artefacts of crime, but current approaches are limited in their ability to link identities across different platforms. We address this through a service-independent model of user profile information, grounded in the details visible on a number of the most-frequented sites on the web. Building on this, we report the details most widespread across platforms and the number of features visible on each site, thus highlighting details of use to both privacy researchers and investigators attempting to cross-link profiles.