CiviCRM enables organsiations to manage their members in one place so that all involved work with the same data. . You can also provide your members with access so they can update their own data. Sending bulkmail or newsletters to your members can be done from CiviCRM. Those activities are registered so that you can always tell what communication you have had with your members. Membership registration and payments are registered in CiviCRM so that you have all data and transactions in one system: CiviCRM!