Knowledge-acquisition research started in the eighties as a small research community focusing on knowledge-intensive problems in relatively small domains. In this paper we look at the influence the Web has had on knowledge acquisition and vice versa. To this end we discuss in some depth four topics, namely the ontology language OWL, the vocabulary language SKOS, the notion of ontology alignment and the potential of semantic search. Even from this limited selection of research issues related to Web knowledge it is safe to conclude that the Web has had a large impact on knowledge acquisition, but also the other way around. © 2012 Elsevier Ltd.