I don't know that anyone has studied social network theory and how it might relate to sexuality. However, there's been a lot of work on social networks in information seeking behavior. I don't know that you could construct a good study on sexual orientation given that your sample is necessarily self selected from the general population. This is something I have to ask about in my stats class. I do think it would be useful to examine how avowed homosexuals and bisexuals found about their wider communities and whether it necessitated a move from their place of birth to a city, specific city at that. This is probably a big reason why Gays as a demographic tends to have high levels of education. I'm betting that a lot of homosexual young people only really come to terms with their sexuality on college both because of the open learning environment and because they have gotten away from their original place and come into contact with people just like them. At any rate, I cam up with plenty of anecdotal evidence, but stastical data is going to be very flawed. I think it would be very instructive to conduct studies of of how people who migrate from a rural to an urban environment change in general. One question of many would concern sexual orientation.