According to this guy "The end of the IT department" is on it's way.

I don't know what kind of research this guy did other than possibly ask a couple of his friends if they thought they knew how to run a computer network.  I do however know what it takes to run the SMB networks of multiple companys all around the Vancouver, BC area.  I can tell you right now, that not many can get away without having an actual network with a proper server.   If you have more than 10 computers in your office you will definitely going to want a server of some kind to streamline file-sharing and security of your files at the very least.  You could probably admin that fairly easily as a non-IT person, but once you progress much beyond that you are going to want someone to make sure that everyone has the correct access and abilities to read/write to the right directorys.  If you are foolish enough to think that you don't need any security for your files, or someone making sure that your backups are being done on a regular basis, and that they are backing up the right things, then you probably deserve the failure your of your business.