As usually argued, tags have “low cognitive cost,” a high-cognitive cost way of saying “you dash them off.” You grab the book, you tag it “cooking” and move on.
That usually a good thing. If you thought about it, you might try to come up with the “perfect” phrase, like “food preparation,” to cover salad-making and other methods that involve no actual cooking, or “food preparation, presentation and related subjects” to cover that book about creating beautiful designs in coffee foam and the manual that came with the Salad Shooter. But coming up with the perfect phrase takes effort and time. You pay for it then and, more importantly, you pay for it when you come to search–for searching is even more about low cognitive effort than tagging.
This much is standard. It’s also clear that “dashed-off” terms cluster well socially. For most domains there are only a few simple terms (eg., cooking, cook books), but an almost endless number of complex ones.
There are problems with this. Indeed, all the “problems” with tagging stem from it. A careful, formal system would distinguish between books about “leatherworking” and books of “leather erotica”. On LibraryThing, both tend to get tagged leather. I won’t multiply examples I’ve discussed before, so I can get to a new one: the Power of Suggestion.
Yak, yak, yak, yak. Joke, joke, joke, joke! Now, what is the white of an egg called? Did you think “yolk”? I’ll bet you did. The children’s joke illustrates something about the brain works. Rapid thought is open to the power of suggestion.
Now catalog and tag the book 9-11 by Noam Chomsky. I’ll bet you tag it “9-11.” The same goes for 9-11 emergency relief, 9-11 : artists respond and 9-11 : the world’s finest comic book writers and artists tell stories to remember. But elsewhere, “9/11” (with a slash) is by far the dominant tag.
9/11 1179 times
9-11 173 times (13%)
Books with “9-11″ in the title
9/11 28 times
9-11 32 times (53%)
Sometimes seeming synonyms actually encode a difference in nuance or perspective (eg., Shirky’s example of “film” vs. “cinema”). In this case, they don’t. There doesn’t appear to be any real difference between “9-11″ and “9/11″ that can’t be explained by the tile. This is why LibraryThing users have “combined” the two tags, an operation we allow, and the combination has not been contested.
Or take Heilbroner’s The Worldly Philosophers. My brother, Oakes, once pointed out, Helbroner’s book about the history of economics is almost invariably to be found in a used bookstore’s “Philosophy” section, not in “Economics.”* On LibraryThing the problem isn’t so acute, but it’s there–152 people have tagged it “economics,” 75 have tagged it “philosophy,” the second-largest tag. Of course, there is some legitimate cross-over between the two subjects. But I don’t think the content alone would merit so much “philosophy” tagging.
This isn’t a perfect example either. It would be interesting to know how many of the “philosophy” taggers had read the book, or what their other tags for it were. But I think it shows a pervasive effect.
The “Power of Suggestion” isn’t a major problem with tagging. But in showing us a flaw, it clues us in to what it’s all about.
*He showed me this when I was quite young, and it stuck. So when I’m in a new bookstore and passing the philosophy section, I often do a quick check to see if my old, confused friend is there again. I’m weird.