The "__ne__" operator in Python is used to compare two values to determine if they are not equal. It stands for "not equal" and is represented by the symbol "!=". When this operator is used, it returns a boolean value: "True" if the values are different and "False" if they are the same. This operator is commonly used in conditional statements to control the flow of a program. For example, if you have two variables, a and b, you can check if they are not equal by using the expression "a != b". This is useful in loops and decision-making processes, allowing programmers to execute specific code only when certain conditions are met.