This module executes one-time actions based on user and entity events. Some use cases for this module are:

• Executing code for specific users, based on contextual data.
• Adding a new user to another entity's entity reference field upon registration or login (e.g. pending group registration).
• Delaying the execution of code during a user or entity event until some condition is met.

Everything this module does can be accomplished using Rules, the main benefit is it provides a very simple API and UI.