[9] Wilhelmus started sex shops and a 'stimulus society' in a cellar in Utrecht that allowed couples to engage in partner swapping.
[20][16] Wilhelmus encouraged readers to provide new child pornography images so as to ensure his magazine's survival.
[17] In 1973, he gave a lecture at a Roman Catholic training institute for working girls in Rotterdam, at the invitation of the school board,[22] and Lex van Naerssen of Utrecht University invited Wilhelmus as a visiting scholar, which led to parliamentary questions in the Dutch House of Representatives.
[23] In June 1975, Wilhelmus partook in a TV broadcast of the NCRV-program Hier en Nu, where he explained how normal sex with children was to him.
[24] In 1986, the PSI subcommittee of the U.S. Senate Committee on Governmental Affairs called Lolita "the most notorious of the foreign commercial child pornography publications".
[25][16] In an interview with the VPRO, Dik Brummel of the NVSH declared that he had bought some issues of Lolita and considered them to be "historical documents".
[27] Wilhelmus became a millionaire,[3][12] but as "one of the most successful"[21] and "one of the most notorious"[1] publishers of child pornography, he ran into great opposition when the social climate started changing and he became more and more isolated.