OK – bear with me on this… I am working on some pretty large ecommerce websites (50,000 + products) where it is appropriate for some individual products to be placed within multiple categories / sub-categories. For example, a Red Polo T-shirt could be placed within: Men’s > T-shirts >
Men’s > T-shirts > Red T-shirts
Men’s > T-shirts > Polo T-shirts
Men’s > Sale > T-shirts
Etc. We’re getting great organic results for our general T-shirt page (for example) by clustering creative content within its structure – Top 10 tips on wearing a t-shirt (obviously not, but you get the idea). My instinct tells me to replicate this with products too. So, of all the location mentioned above, make sure all polo shirts (no matter what colour) have a canonical set within Men’s > T-shirts > Polo T-shirts. The presumption is that this will help build the authority of the Polo T-shirts page – this obviously presumes “Polo Shirts” get more search volume than “Red T-shirts”. My presumption why this is the best option is because it is very difficult to manage, particularly with a large inventory. And, from experience, taking the time and being meticulous when it comes to SEO is the only way to achieve success. From an administration point of view, it is a lot easier to have all product URLs at the root level and develop a dynamic breadcrumb trail – so all roads can lead to that one instance of the product. There's No need for canonicals; no need for ecommerce managers to remember which primary category to assign product types to; keeping everything at root level also means there no reason to worry about redirects if product move from sub-category to sub-category etc. What do you think is the best approach? Do 1000s of canonicals and redirect look ‘messy’ to a search engine overtime? Any thoughts and insights greatly received.