I'm in a small office, running SBS, and AD adds a lot of overhead and little benefit. If we weren't a nonprofit that could buy from TechSoup, it would add a lot of expense in licensing costs.

The value of single sign on is being eroded by the proliferation of web apps on the internet, which usually have their own accounts. Passwords get stored in the browser (and in peoples password lists).

So, you have an in-house database, Outlook and Exchange, the file sever, and that's it. Most of your other stuff is on the web.

People entering the organization know how to use web databases. They're on Facebook

They don't really "get" the Outlook and Exchange integration. They don't always know how to use file servers - they prefer to email files around. They don't know databases via non-web clients.

These traditional applications start to feel like a burden.