blogs.dir is supposed to be used to separate content for the different blogs on a network install of WordPress (MU or 3.0+ with networks enabled), however, I’ve not been able to find a clear guide to using it. Can someone shed some light and maybe post a few links to information on how to set it up, what to put in there, what the permissions should be set to, etc. ?
blogs.dir was the way to handle specific blog plugins and themes when it was WordPress-MU
but since version 3 came out and the WordPress-MU was integrated into WordPress Core and introduced WordPress Multisite, that’s no longer the story.
WordPress Handles the creation of the new blogs/sites in the database and mainly in the background so you won’t see too many things changing, but it also includes a new menu in the admin “Super Admin”
which lets you handle the content for all sites in one place and they all site in one place.
so basically WordPress handle this issue of `blogs.dir’ for you.