Email housefile refers to the part of housefile that includes email addresses. Most part of email housefile are from newsletter subscriptions but not exclusively.
Email housefile helps companies build revenue with email housefile program and strategy. The vast majority of email marketing actions are based on housefile. Only email acquisition campaigns do not use it.
From case to case, email housefile may be the source of a large part of company sales and thus, the stakes are high for email housefile development or list building.