I can create workflow entity methods and workflow tasks. I always confuse the two, since I don't know what the difference is, conceptually. When to use one, and when to use the other? What are the main differences and why are there two types in the first place?
It is all about the parameters the function/task needs. If it does not need any parameters then you can get away with a lot less programming, just do what you need: that is a custom method, if your task requires some sort of configuration settings and options then you need to implement a configuration screen: that is workflow task.
http://corebos.org/documentation/doku.php?id=en:devel:addworkflowfunction