Faceting is a deceptively hard problem to solve because it requires understanding the features of the products within the categories of products within the ecos

Faceting is a deceptively hard problem to solve because it requires understanding the features of the products within the categories of products within the ecosystem of products a seller is selling, and dividing them up based on how a customer is likely to be thinking about the products. If you're selling clothing, the customer is likely going to mean something different with the word "long" than they would mean if they were searching for foods. Within different categories of clothing the word "long" is going to mean different things.