as i said in my question is this usefull or SEO or will this effect negativly ? what i mean is using subdomains for each part of my website for example i have a website with four main Products. so i will create subdomain for each product but the whole website design and all stay same so users wont find any difference when they move from one product to another using menu. so not only SEO i think this will help people to remember the URL much easier for each product. and they dont want to go to homepage always when they need only information about specific product. i know the SEO juice will not be spread easily like this way but how about using Sub domain redirecting to sub folders ? product1.domain.com --redirect.to--> domain.com/product1