That's not precisely correct. In the old days, we typed in our favorite bands/books/music. The attempted canonicalization created some amusing interpretations

That's not precisely correct. In the old days, we typed in our favorite bands/books/music. The attempted canonicalization created some amusing interpretations of song as band, book as author, band as book, etc. It has also made it exceptionally annoying to get feed updates from the 900 bands, actors, movies, songs, etc. that I said I liked and now have to "unlike". I think you could correlate people within a certain confidence, but because of the nature of the data, you would have to expect a surprisingly large dissimilarity of interests within a clique over a certain account age based on this noise. Not 90%, but higher than the real value.