In 1993, in collaboration with the Fraunhofer-Gesellschaft Cailliau started the European Commission's first web-based project for information dissemination in Europe (WISE). As a result of his work with CERN's Legal Service, CERN's director of Future Research Walter Hoogland signed the official document that released the web technology into the public domain on 30 April 1993.
In December 1993 Cailliau called for the first International WWW Conference which was held at CERN in May 1994. The oversubscribed conference brought together 380 web pioneers and was a milestone in the development of the web. The conference led to the forming of the International World Wide Web Conferences Steering Committee which has organized an annual conference since then. Cailliau was a member of the committee from 1994 until 2002.