What Are the Differences Between Activity Timeline and Activity History?

The activity timeline and the activity history view are two different views, and behave differently.

One difference appears when you send a list email to multiple contacts, leads, or campaign members. On each recipient’s activity timeline, the list email appears as one entry. When you click View All to view the recipient’s activity history, however, every email sent by the list email is shown.

For example, send a list mail to two contacts in an account. On the account’s activity timeline, the list email shows as one item. Then click View All on the Activity Timeline to open the activity history view. Two emails appear: one for each of the contacts in the list mail.