What does the "follow" button do on a Coach Profile?

When a user follows a coach, they'll be notified if the coach answers a question in a goal they are part of.

An example: if someone is in the "Run" goal, and the coach answers a question, the user will be notified. Users will also see coach check-ins in their activity feed. 

However, we are planning to expand this very soon. We have ideas around coaches reaching out to their followers, for promoting plans, their coaching, advice, etc.