Lesbians are quite common in Second Life. Yours truely knew personally no less than 5 sims dedicated to lesbians, and lesbians only. (Males are forbidden)
Sex is not just for heterosexuals. In this anonymous fantasy land, true nature shows itself quite openly sans social restrictions.
In mere 2 weeks time (about 11 hours per day), yours truely discovered how great numbers there are of lipstick lesbians or bisexuals girls. (this impression is purely empirical and is of course not a substantial observation. Also, since i'm not interested in having sex with men, i have not yet ventured forth into the exploration of male gay communities.)
In a virtual world, meeting new people is far less costly than in real life. You could meet a lot people and get to know them in a short time. (after all, you can literally fly in Second Life) And in a virtual world, people are less finicky about their true nature. (since there's little to no risk; as opposed to real life's risks of reputation or job or time-drain or emotional stress (for example, suppose a very personal embarrassing moment came up in Second Life, or someone made you angry, you can simply =poof= and disappear and reappear somewhere else, and leave your antagonists to gawk at the empty space that once was you)) So, in a way, you learn about people's desires and heart far faster and quicker than in real life.
A virtual world environment such as Second Life, therefore, can be a platform for psychological or behavior research thru statistical means.