Get it All

Summary:  Creates an entry in the wp_blogs table (or equivalent) for a new blog with the domain $domain, the path $path and within the site $site_id.

Detail:  This is one of the functions called when a new blog is created.  It’s not the whole process, and unless you have a specific reason for calling it, is probably best left to itself.  It only really performs two functions, the first being the insertion of the new blog into the database, and the second being a refresh on the wp_cache to include the new blog.