The abstract of Balog looked a two areas concerning people search, profiling people and enabling search of those people based upon both the topical and social profile. Who is an expert on X? Who do I know (or get introduced to) someone who is an expert on X? His research seems to be just beginning.. I'll be checking his page for new papers.
Both of these topics are obviously of interest to Others Online and the idea of connecting people together through a common topic or set of topics that are learned as implicitly related to the users.