Hi,
On every new CiviCRM install, I've had the same question about the difference between CiviCRM (the mass mailing module) and the send mail feature (from and individual contact and a search result). The question is when to use one or the other.
I understand than historically, these two features comes from both end of the spectrum, CiviCRM was made to send newsletters and bulk emails, and the send email is a replacement of sending a mail from your mail client. However, you can have a mailing list of a handful of contacts, and you can send "individual" emails to several dozen contacts.
