A system, method and program product for a computer-based project collaboration system using a data log for cross-domain collaboration. A cognitive log stores log entries based on domain-specific project data sources. An ontology translator includes domain-specific ontologies and a mapping ontology that defines relationships among the domain-specific ontologies. A cross-domain query includes domain parameters from one domain-specific ontology and returns and displays results based on log entries with domain parameters from another domain-specific ontology using the ontology translator.