Code clones - Good, bad or ugly?

Code clones (the products of code cloning or copy and paste programming) can be a menace when it comes to long-term source code maintainability. While they seem harmless at first, they will do their damage after a few development iterations – exactly when it is too late for an easy fix. Neglecting to manage clone instances along with each other during a bug fix or a feature development of any of them will likely result in the inconsistency of the source code.