The Virtual Language Observatory (VLO) is an open-access service provided by CLARIN offering uniform search and discovery functionality for language resources and tools. The metadata is sourced regularly from over fourty CLARIN centres that provide resources or tools of interest to scholars. On top of that, CLARIN harvests from a few dozen external providers that also offer relevant content. However, the collected data is often heterogeneous in terms of content, structure and language. The number of resources is so huge that reaching a full-scale overview is virtually impossible without technical support. This principle is exploited by the VLO, which maps a wide range of metadata so that any community can adopt it with minimum effort.