I'm doing the phd Communication/Information program at UTK. I think a lot of people simply think about a phd in Information Science (often assumed to be one in the same 100% of the time as Library science)and don't think about the fact that its not just libraries that can be, and are being, studied. Most phd's in the discipline are now combination or interdisciplinary and can be used in a variety of ways and fields than what someone might initially think.
Not that there is anything wrong about studying libraries. Just that there is a lot more to be studied in combination fields.