This vendor-supplied help article provides information and examples on how tracking happens within Salesforce Marketing Cloud. Tracking in this context refers to sending messages to recipients and all of the interactions recipients have with them. We refer to each interaction as an event but as a fact when stored in the database. The first event that occurs in any interaction with a recipient is a Send. Other interactions we recognize and store are as follows:

• Deliveries
• Bounces
• Opens
• Clicks
• Survey Responses
• Conversions
• Forwards
• Complaints
• Unsubscribes