The concept is nothing new. After all, it is one of the primary purposes of librarianship. Interactive assistance provides customized help for particular users in particular situations. Put another way, interactive assistance adds the next level of intelligence to information systems. Interactive assistance does not necessarily mean artificial intelligence or expert systems, but that would be nice.
Interactive assistance is simply a way of specialized help for specialized situations.
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.