Depends, Google treats sub domains as a new domain. So, if you want to benefit from your domain authority I would recommend domain.com/blog . If for some reason you want to separate it completely, go for a subdomain . But in my opinion, a subfolder will do just fineThis is for a large organization site.
I have read all the replies. Are subdomains really not given any boost? A while ago I thought I read about people buying authoritative domains and making a bunch of subdomains to point them to other sites, didn't I?
I will make it in its own folder.
The other thing I wanted to ask, if the site already uses Wordpress, can you still have it installed in there for a blog?
The site is one of those tall sites that doesn't have other pages other than the blog.
This should be cool.