I am working on a project where I have a basic site with a sets of modules and configurations. Currently when I get a new client for this project in order for him/her to use their own site, I setup a subdomain, load a basic DB and copy the basic site files over.
This setup has work for me, but now I am having to deal with more clients and the manual process will just make it hard to manage and maintain. Ideally I will love to have it a single set of files will connect each user DB and I don't care if instead of subdomains (they are nicer) I have to use sub-directories.
What will be best for this setup multisite or multiple sites, and will it make sense to have a centralize account (open id) server?
Note: I was thinking in register the users in a single place and then they can login into their private sites using this centralize account system. Otherwise each site will have to have a user 1 account with a password to be manage for each site.