Never contacted a faculty member, but I was accepted to several good programs. I strongly think that it is unnecessary to contact professors prior to applying to PhD programs. For other majors such as engineering or nature science, they usually have independent labs charged by individual professors. In that case, funding conditions hinge on each lab's varying situations, so you should probably send an email to professors so as to ensure a place. However, in most sociology departments, members of admission committees take precedence over each professor's needs. What's more, sociology doctoral students normally do not solely work under just one professor but collaborate with multiple faculty members to pursue research. It is okay to use email to simply gather some information about the department. But 'sucking up' rarely guarantees your admissions, in my opinion. Some might say that "I contacted a professor then got admitted" - I'd say you would have been accepted, too, without having a conversation with professors because you're basically qualified.