It’s possible, but it depends on how you use them.
Some SEO experts like to set up category-based subdomains for blogs. The advantage here is that the keywords in the category name are at the front of the URL, in the domain name.
So, for example, a post about using subdomains as blog post categories might then have the URL:
But, it’s hard to see how this is significantly better than the more conventional approach of putting the category into the permalink structure:
This approach may be most helpful if you want your category pages to be landing pages for Search Engine results.
