In the eyes of the search engines, from an seo point of view, are subdomains treated as a separate domain from the tld? no it will not treated as a separate domain Although subdomains are still considered to be parts of websites which are attached to their main URLs over the net, but you can find a lot of big portals online, comprising tens or even hundreds of subdomains, each used to target new sets of keywords, having their own ranks and placements online as well as link packs. Using subdomains can be especially great when a big portal is going to offer