Hello, i would like your advice on a dilemma i am facing. I am working a new project that is going to release soon,  thats a network of users with personal profiles seperated in categories for example lets say the categories are colors. So let say i am a member and i belong in red color categorie and i got a page where i update my personal information/cv/resume as well as a personal blog thats on that page. So the main site is giving the option to user to search for members by the criteria of color. My first idea is that all users should own a subdomain (and this is how its developed so far) thats easy to use and since the domain name is really small (just 3 letters) i believe subdomain worth since personal site will be easy to remember. My dilemma is should all users own a subdomain, a subdirectory or both and if both witch one should be the canonical?

Since it said that search engines treat subdomains as different stand-alone sites, whats best for the main site? to show multiple search results with profiles in subdomains or subdirectories?

What if i use both? meaning in search results i use search directory url for each profile while same time each profile owns a subdomains as well? and if so which one should be the canonical?

Thanks in advance,

C