CiviCRM's means of keeping track of all sorts of interactions with contacts: e-mails, meetings, donations, event attendance, etc.
Activities are a key concept in CiviCRM, providing a unified place to record and view the history of interactions between your organization and your constituents, clients and partners. You can use them to track meetings, phone calls and other activities that you set up. Activities are also used by all of CiviCRM's components to record things like when contributions are made, when people come to events, sign petitions, etc.
All activities happen at a specific point in time. All activities involve at least one contact, and many involve more than one. Activities can be assigned to staff or volunteers, and an email is automatically sent to the assignee.
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