A week or two ago I began writing a few thoughts about large-data based algorithms and retrievability. It was spawned by the Unreasonable Effectiveness of Data position paper by a couple of notable Googlers, which then led to a brief discussion.
My main contention was that by relying to heavily on algorithms that are based solely on accumulations of large-data, and by not offering users exploratory search options to turn off the large-data, popularity bias, searchers would be unable to ever find certain pieces of relevant information. This is not even a matter of knowing the correct query terms to use; I argued (backed up by published research) that even if you knew the correct terms, you still could not find certain pieces of information.
Well, now I want to write about the other half of the equation: What do you do when the information is retrievable under some term, but you just do not know that term? Why do search engines not give you more help with finding information which does exist if you know exactly the right word to use, but for which no reasonable person would ever know the correct word?
Let me give an example: Hidden Cafes in Prague.