Activities
Use this apis to search for activities done by Profiles or Contacts. Activites are such things like sending a complaint, closing a ticket (case), expressing gratitude, receiving a reply with a promo code, posting, sharing, liking, retweeting, unliking, and more. Usage scnearios of these activities are marketing lead scoring, CRM completeness, etc…
Contact Activities
Lists activities done by or with all the profiles of a contact. See Contact Activities API
Profile Activities
Lists activities done by or with a particular Profile. See Profile Activities API
Case Activities
Lists activities done in association to a particular case. See Case Activities API