When you add an agent to a list, you are adding them with the intention of exporting their production data either immediately or at a later time, and organizing their data by whatever search parameter you were initially searching for.
Following an agent does not add them to a list, but that agent will pop up in your dashboard, where you can easily track the agent’s recent purchase activity and listings + open houses.
You can both follow an agent and add them to a list, as this is a great way to not only save the agent's existing data, but keep track of new data as well.
To follow an agent, head to their profile and hit the “follow” button under the contact info. You can also add an agent to a list from their profile as well.