Access to the Internet has increased dramatically over the past decade as has its use for meeting sexual partners (e-dating), particularly among gay men. Between June 2002 and January 2004, 128 gay/bisexual men living in London were interviewed one-to-one about their experience of e-dating, sexual risk and HIV prevention. The men were recruited both online (through the Internet) and offline (in clinics and the community); 32 men were HIV-positive, 59 HIV-negative, while 13 had never had an HIV test. A key finding was that both identity as well as anonymity are vital to e-dating. Through a process of online filtering and sero-sorting, HIV-positive men are able to meet other positive men for anal sex without condoms. While this does not present a risk of HIV transmission to an uninfected person it does have implications for the potential transmission of other STIs such as syphilis and LGV. Through e-dating, HIV-positive gay men can also avoid abuse, discrimination and sexual rejection. Our findings do not support the suggestion that the attraction of e-dating is that it affords absolute anonymity. We found that the gradual expression of identity is vital for e-dating among gay men. Internet-based HIV prevention campaigns need to take account of the different ways in which gay reflexively manage aspects of their identity online.