Maybe I'm wrong here. I haven't done much research, but from what I've gathered from my study of the history of literature, this concept of making lists and ranking works, whether they be books or songs, is rather new. I've never seen it done in any books written in the early 20th century and before, but to be fair, it would more likely be done in less reputable publications (i.e. newspapers, magazines). I would be very curious to find out when we first started attaching a number rank to things.
By this I do not mean something like a best seller's list. That is mere statisics, which I'm sure they kept track of for hundreds of years before our Top 40's and New York Times lists. What I mean is the basic aspect seen in most reviews, what I'll call "the five stars concept." It's in every aspect of our media use. I use Zune player, which uses a simplistic ranking system, either I "heart" a song, "broken heart" it, or leave it alone. But is it ever really that simple? Most of the music I have has a heart next to it. None of it has a broken heart, because why would I keep music I didn't like. I have around 10,000 songs, and I'm sure I don't love--as the heart would indicate--every one of them.
But is the star system any better? I'd say it stands to reason that anyone reading this has used Amazon. They make things a bit more complex with their five star ranking. One star means "I hate it," two "I don't like it," three "It's OK," four "I like it," five "I love it." It makes sense from a marketing standpoint. If you tell Amazon you loved The Warden by Anthony Trollope it will be able to recommend several other books people who also loved it ranked equally high. But from a review standpoint, what does that tell us? Say for example, the reviewer gave it four out of five stars. He "liked it." But that tells us very little about his opinion of the novel. I like chedder cheese and I like The Warden. One of those I could talk about for a solid hour, and it's not chedder. I know much of the ins and outs of Trollope's first Barsetshire novel. I found many parts admirable from a moralist perspective, but as a solid piece of literature, it is lacking. Judging from my ranking of it, one might easily assume that I simply enjoyed it, which is far short of my actual opinion of it.
But I think most people are agreed that this ranking system we find in our reviews is flawed. The deeper question is why we find a need to do it. Beyond the marketing aspect, we see the internet filled with lists: "best albums of the year," "most important novels of the 20th century," "coolest summer movies." When I was younger, I would make lists of my favorite albums for no reason but to do it. It's as if we're fullfilling some need to validate our opinion. Maybe subconsciously, we feel like it matters if 257 people ranked some movie on Netflix rather than 256. But who has ever watched a movie based on rank alone? I haven't. I've read reviews certainly, but I watch the movie based on if it sounds interesting or I like the director/writer/actor. On occasion, I will watch something based on recommendation alone, but never on rank.