The functionality is activated by enabling the Portal-module. When you send a document to a customer (quotation, invoice), your customer will be able to signup to get all his documents, read your company news, check his projects, etc. It can be disabled via Settings > General Settings > Activate the customer portal (and uncheck the checkbox).

Unfortunately the email-footer is hardcoded and automatically added if a partner is associated with the current document. After some extensive testing we found that the portal module is not (yet) suitable for our company. You best leave this module disabled until the following issues are resolved:

• Footer can be customized through the user-interface
• The correct server url's can be configured somewhere
• It is exactly clear for the user when emails are sent to customers (maybe ask via popup dialog?)