The downside of searchability is it requires users to articulate their information need and formulate it in terms of the systems' query language. No matter how well a large information system exemplifies readability, browsability, and searchability, there are always to going to be people who cannot locate the information they seek even though it exists within the information system. The purpose of interactive assistance is to reduce this possibility. 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.