@JamesBrownlie HubSpot provides the activity history to keep track of all the email conversation with a prospect/contact. But if you want to track email conversation for the mass audience then this will not be a great solution.
The best way to follow the engagement is by using lead scoring, where you can assign the lead score based on the email engagement and also change the lead stages accordingly to keep track of the complete lifecycle.
Thanks @Kapil_Arora. I'm simply trying to ensure that our company has visibility of every conversation that occurs throughout the deal. Do you know if that is something that HubSpot can provide at all? Lead scoring doesn't seem like it would help us in this situation.