While I find facets extremely obnoxious to create, I cannot deny the fact that they are incredibly useful to me as a patron. On Amazon or MCPL or IUCAT, I can quickly find exactly what I’m searching for simply by slicing out options that I don’t need. Other times, facets are the easiest way to browse items I may be interested in. I may decide the format and genre of a CD I want and go through the top rated lists from there.
It’s actually hard to provide too many facets. Another benefit of them is that users can choose which facets they actually need. Going down a list, one might only need ‘Format’ and ‘Language,’ thus skipping over ‘Year,’ or ‘Subject’ altogether. In this way, one can narrow down items exactly as needed, giving the user the choice of how to divide results.