The postings made to Internet forums by relatives and friends of people with breast and prostate cancer are described. Women post very frequently on the prostate cancer forum and assume a communication style that is similar to women elsewhere, prioritizing emotional forms of communication over the informational forms preferred by men and showing only mild signs of accommodation to a male style. Men on the breast cancer forum are in a minority and are often responding to the current or anticipated loss of a partner. Their communication behaviour is radically different from that required by dominant conceptions of masculinity. They prioritize emotional communication and the emotional welfare of family members. They experience this new form of communication as unsettling to their conceptions of traditional masculinity. Internet cancer support groups thus favour a form and content of communication generally associated with women's culture.