Apples and oranges. A monad is just an idea; that of storing computations as values. This is useful because these computations can be composed together in a manner not unlike that of a pipeline in shell scripting. Different monads define different ways of composing these computations leading to vastly different semantics.

Here's a nice video that explains monads fairly simply:

http://www.youtube.com/watch?v=ZhuHCtR3xq8