Some services provide aggregate or accrued stats for different users of their systems. For example, Twitter provides the current number of friends, followers, favorites, and statusus a user has via its API. 

Being able to represent such values in a conventional way in activity streams could be useful as a way of building out an actor's profile. 

This information could also be used for a relative reputation score.

Attributes

• social metrics: friends, followers, contacts, ratio of bidirectional relationships
• age: how long the user has been using the system, in days
• recency: how recent the user was last active (in seconds)
• liveliness: percentage of active days on a service (i.e. versus days of inactivity)

Prior art

• Flickr Stats API (docs)
• UserLabor.org
• Community Equity