This is nothing new. Libraries, huge information systems, have always had librarians. The larges of information systems will require some sort of extra, interactive assistance in order for their services to be most effective. This interactive assistance could simply be a person at the other end of a telephone or an Internet Relay Chat. Based on the answers, other questions would be asked.
Interactive assistance can be proactive or reactive.
Proactive interactive assistance queries users for the information needs. It analyses the answers to the queries and either formulates possible solutions to the information need or continues the query process. A reactive assistance model would only provide possible solutions after being asked questions by the users. The difference between these two models is similar to the difference between browsability and searchability. Both browsability and proactive assistance layout ready-made solutions or information paths.