Signaling is any activity whose purpose is to cause others to form beliefs your abilities (whether those beliefs will be correct or not). Some signaling is performed exclusively to impress others (to improve your status), and in some cases isn't even worth that. In other cases, signaling is a side-effect of the otherwise useful activity.
For example, if doing something is easy for one type of person and hard for another type of person, you might do that thing just to get people to think you're the former type of person, even if the thing isn't in itself worth doing. This could explain many facets of human behavior, and reveal opportunities for reducing waste.
Not all signaling is about abilities. Signaling can also be about personality, current emotional state, beliefs, loyalty to a particular group, status within a group, etc.
Posts by Robin Hanson:
- Do Helping Professions Help More? and Gifts Hurt
- Excess Signaling Example
- A Tale Of Two Tradeoffs
- Why Signals Are Shallow - "We all want to affiliate with high status people, but since status is about common distant perceptions of quality, we often care more about what distant observers would think about our associates than about how we privately evaluate them."
- Signals Are Forever