Methods, systems, and computer storage media for providing supplementary item information on communications-based compatibility features for a primary item in an item listing platform. In particular, communications-based compatibility features are extracted from user communications about the primary item to identify additional features of the item. In operation, a supplementation engine of an item listing platform, accesses user communications for the primary item. Supplementary item information is generated for the item, where the supplementary item information includes a communications-based compatibility feature associated with the item. The communications-based compatibility feature indicates that the primary item is compatible with the secondary item, a non-standard feature (e.g., a feature not provided in a feature set of the primary item), or a demographic feature (e.g., age). The supplementary item information is provided to cause presentation of a user interface element corresponding to the communications-based compatibility feature on a user interface of the item listing platform.