Hi Kyle,
Sorry for the long post but I would like to explain the thought behind the feature request.

Nowadays, social networks are sorted by algorithms and AI that analyse your behaviour. That includes the newsfeed (which is at the end what activity is, kind of). That means your view of the world is basically controlled by algorithms.

I want the users to get back an opinion by being able to control again what they see in their newsfeed on my site. That means that the user should be able to set the filter of what he/she sees on the newsfeed per profile and forever (unless he wants to change it).

Here is how I had envisioned it:
_You have a field where the user can set what filter he wants to have as standard. This should be a multiselect (obviously)
_Each field can be set to a certain module ID. This is to ensure that if there are several CB Activity modules or streams, the user can filter each activity stream using a field.

Thinking about it, you could "easily" introduce a different type of field which then controls a user defined stream.