CiviCRM also has 4 important components that take it beyond a simple contact management system
civiMEMBER
CiviMember provides flexible membership management for your organization, along with convenient online signup and renewal. You can set up different membership levels and divide these between different parts of your organisation. For example by region. You can then allow people to sign up for the appropriate membership online and add their own details to your system.
civiEVENT
CiviEvent provides integrated online event registration and management for paid and free events. You can create your own event sigup pages with different levels of participation and track participants. It's easy to add custom fields for special requirements that you may need to offer, such as dietary requirements, disability access, etc. You can then search for participants by event, event type, participant role, etc. Users can export events as iCal files or subscribe to iCal feeds.
civiCONTRIBUTE
CiviContribute is an online fundraising and donor management component which enables you to track and manage contributions to your organization. These can be donations, membership dues, event fees, etc. You can automatically generate receipts, and track thank-you notes, and import and export contribution data to/from other systems like an accounting package. Past contributions are visible when viewing any contact record.
civiMAIL
CiviMail is a robust mass-mailing component which allows you to engage your constituents with personalized email shots and newsletters. You can target mailouts to CiviCRM groups and track open rates, click throughs etc.