In June 2014, the NISO Open Discovery Initiative (ODI) working group published its best practice recommendations for indexed-based discovery services. Addressing the need for a unified search, these services use an aggregated meta-index and enable users to query a wide range of resources – both licensed and free – from multiple providers. Discovery services have largely supplanted the previous generation of metasearch systems and offer superior performance, much wider search scope and no limit on the number of results retrieved by the system. Although these relatively new discovery services have been widely adopted by libraries on a global basis, the ODI recommendations should assist with the further development of this industry. This article provides some background for the ODI, a summary of the published recommendations, and a call to action.