In a recent blog post, Vegard Sandvold proposed a taxonomy of search systems based on two dimensions — algorithmic vs. user-powered and information accessibility. The first dimension represents a tradeoff between systems and people in terms of who does the information seeking, and the second one measures the ease of finding information in some search space. His blog post was intended to solicit discussion, and, in that spirit, here is my take on his ideas.
Recently, I’ve been involved in a lot of discussions about exploratory search on this blog and in comments on The Noisy Channel. One way to look at exploratory search (and there are many others!) is to separate issues of interaction from issues of retrieval. The two are complementary: for example, recently Daniel Tunkelang posted about using sets rather than ranked lists as a way of representing search results. This has implications on one hand for how the retrieval engine identifies promising documents, and on the other for how results are to be communicated to the user, and how the user should interact with them.