Email Service Provider (ESP)
An Email Service Provider (ESP) offers email marketing or bulk email services. Neither of these terms should be confused with spam or the sending of unwanted or unsolicited bulk email of a marketing or otherwise offensive nature.
An ESP will provide a wealth of tracking information showing the status of email sent to each member of your address list. ESPs also typically provide the ability to segment an address list into interest groups or categories, allowing the user (Advertiser) to send targeted information to people who value the correspondence.
In regards to OPTIZMO
An Advertiser might go to an ESP to utilize there services for email marketing. In turn, the Advertiser sets up an account with Optizmo so we can manage their suppression lists. The Advertiser would then give the ESP (or Mailer) access to the Optizmo system to either/both upload and download the appropriate lists for emailing purposes.