Search versus Recommendation: Not The Only Tension

Greg Linden has an interesting post on Search on a domain like YouTube.  I reproduce it here because I would like to elaborate on it:

The article focuses on YouTube’s “plans to rely more heavily on personalization and ties between users to refine recommendations” and “suggesting videos that users may want to watch based on what they have watched before, or on what others with similar tastes have enjoyed.”  What is striking about this is how little this has to do with search. As described in the article, what YouTube needs to do is entertain people who are bored but do not entirely know what they want. YouTube wants to get from users spending “15 minutes a day on the site” closer to the “five hours in front of the television.” This is entertainment, not search. Passive discovery, playlists of content, deep classification hierarchies, well maintained catalogs, and recommendations of what to watch next will play a part; keyword search likely will play a lesser role.

My feeling is that the dichotomy that is being drawn does not exhaustively cover the space.  I would characterize the space using the following two orthogonal dimensions: (1) Information Need Clarity and (2) User Engagement.  The first dimension (clarity) is related to the degree with which the user understands his or her own information need, i.e. has something specific in mind that he is looking for and/or understands what he needs to do to find it.  That need may either be well understood, or (to borrow Nick Belkin’s terminology) “anomalous”: The user doesn’t know what he or she doesn’t know.  The second dimension is related to the level at which the user applies himself to the information seeking process.  That level may be active or passive.

Greg points out two modes: “Active Understood” (typical navigational web search) and “Passive Anomalous” (entertainment/discovery/recommendation).  But I believe that there are more than these two modes.  A large, interesting design space opens up when one realizes that information seeking can be “Active Anomalous” and “Passive Understood“.


Exploratory Search is a good example of Active Anomalous seeking.  One doesn’t yet fully know or understand what it is that one is looking for, but at the same time one is willing to engage with an information system in order to discover what it is that he or she does not yet know.  And the system itself is designed not necessarily toward trying to answer a well understood need, but toward helping the user map out and better comprehend a space.

Collaborative Information Seeking (see here and here and here) is a good example of where an need may be well understood, but a user does not necessarily have to actively express every last query detail in order to get more information on a topic.  Why not?  Because when User #1 is explicitly collaborating with User #2, an algorithmic mediation engine can push some of User #2’s activity on to User #1 without requiring User #1 to make additional effort.  Note that I am not implying that every aspect of collaborative information seeking is passive; quite the contrary, as it requires at least one co-collaborator to be active.  I am only pointing out that it is a domain in which it becomes possible for a user to passively obtain specific information on a well understood need.

There is a lot discussion in the Information Retrieval Community on the similarities and differences between Search and Recommendation.  A fruitful tension opens up as one travels back and forth along the diagonal from Active Understood to Passive Anomalous; the two approaches often end up complementing each other.  Where I see much less discussion is on the tension that opens up along the other diagonal, between Passive Understood and Active Anomalous.  When Exploratory Search meets Collaborative Information Seeking, it yields Collaborative Exploratory Search and a whole host of interesting possibilities.  Over the coming year I will be blogging more about the tension along this alternative diagonal (both here at on the FXPAL blog) and what it means for the Information Retrieval systems I and others are designing.  Happy 2010!

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4 Responses to Search versus Recommendation: Not The Only Tension

  1. Standing queries (such as Google Alerts) are another example of a passive, well-understood need.

  2. jeremy says:

    Oh yes, good point! Hmmm.. does my taxonomy hold up, in that context? Is there a fruitful tension between standing queries/alerts and exploratory search? I’ll have to think about that some more.

  3. Pingback: Weekly Search & Social News: 01/12/2010 | Search Engine Journal

  4. waqas says:

    YouTube wants to get from users spending “15 minutes a day on the site” closer to the “five hours in front of the television.”
    i am totally agree with you on this. we can save our time and also can entertained ourselves by suggesting to youtube about our choice. can you tell me either the youtube will allow all kind of movies and clips for the users?

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