Modern trends in knowledge-dominated economy I society are (i)from "capital-intensive business environment" to "intelligence-intensive business environment " and (ii) from "product push " strategies to a "consumer pull" management. This leads to Mass Customisation (MC), assuming mass productions of individually customised goods and services at mass production costs, and e-Manufacturing, based on intensive use of WWW-technologies in the manufacturing part of e-business. Technology of Knowledge Fusion (KF), based on the synergistic use of knowledge from multiple sources, is a good basis for MC information support in e-manufacturing. The paper discusses a concept of a KF technology and its applications in the area of e-manufacturing based on utilizing ontologies and intelligent agents.