The way software properties are defined, described, and measured, is different across different domains. When addressing these properties, several challenges commonly emerge, among which: synonymity, polysemy, paronymy, incomplete and inconsistent specification. In this paper we introduce PROMOpedia, an online encyclopedia, to tackle these challenges. PROMOpedia uses a web-content management system coupled with crowd-sourcing of scientific contents related to properties and their evaluation methods. The core concepts of PROMOpedia are built upon a property models ontology previously proposed by the authors, and is intended to target the needs of both researchers and practitioners. Website: http://www.mrtc.mdh.se/promopedia/