Shadow IT, aka Rogue IT, has a bad rep. And it probably should. It can compromise security, increase IT costs, result in dangerous leakage of data and IP, and get people fired. It also generates friction and thus expands the already too wide rift between developers and IT.
In a nutshell, Shadow IT is practicing IT without IT’s permission. I’ll focus on Shadow IT as practiced by developers here. A common example is bypassing the internal resource request process and spinning up VMs on AWS for application development. Or using a DBaaS like MongoHQ or Google Cloud Datastore for instant access to a fast, redundant, reliable, always-available datastore. Other examples include using DropBox to store corporate files, using Evernote to store notes, github to store source code, collaboration software too like yammer, and LastPass for password management.