The hell-sewer is real, but banning shadow IT is not the right answer.
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Above is the answer to your question, but it raises the question - what is the right answer to shadow IT?
The problem with this question is that it sounds like ONE question, when in reality it is a many segmented question. You need a way to characterize the shadow IT in question so that you know what approach you should take.
If shadow IT overlaps with governance, then it should not be shadow IT.
If shadow IT does not, then it's probably fine to stay that way or be replaced at some point by a MVP.
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That answers the question I raised, but now I've raised another question: WTF does "overlaps with governance" mean???
And this is where the nightmares begin!