There is all sorts of talk lately in the Ruby on Rails community about decorators and presenters.
What is the essential difference between the two? If there is, what
I suggest you to check this - Exhibit vs Presenter.
Decorator is a design pattern that is used to extend the functionality of a specific object by wrapping it, without effecting other instances of that object. In general, the decorator pattern is an example of the open/close principle (the class is closed for modifications, but available for extensions).
Both the exhibit and presenter patterns are a kind of the decorator pattern.