One of the general criticisms of online socializing is that so much revolves around profile systems. Many people feel a great amount of pressure to create profiles that should inspire certain reactions in "most" people through a picture and/or very few words. Finer detail and more creative representation may be more honest or expressive... However, it reduces one's chance of being recognized by many people as a "good" member of a larger category of desirable people. This is a dilemma. I think it's present on most sites. I'm not convinced that the "shallow" factor is actually more than in face to face interactions. Perhaps it's a different kind of bias, and it affects some people more than others.
I often feel like a minority inside a minority when it comes to sexual networking. Between my own particular interests, a general preference to select fewer "good" matches rather than numerous "possible" ones, and the distorting effects of searching by profile... I don't expect any site to generate hundreds of hits at a time for me. That said, there are usually some gems buried among the mountains of data. I do believe there are opportunities online to talk out issues that might be less practical to work through in the flesh. There is also some opening for connecting through fantasy and selective presentation of self, first. Whether that's helpful depends on mutual goals (and fantasies).
I suppose networking sites, Second Life and talkers are different from "dating sites" proper. I expect that traditional dating areas would focus more on individual searches. In the networking sites, one can also spend time in various communal rooms; that adds a different way to get to know people. Second Life and other sites where people can invest money and simulate environments or poses might have more potential for exploring whether people have compatible ideas about wealth, space, and visual style. Some people see this as too simplistic a model. Others find that it helps select/cut to what could be ideal or possibly, most important.