If you send out an email newsletters, do you transfer include the email ID of the recipient as a clickthrough parameter or do you use an indeciperable recipient code?
If you transfer the email ID (e.g. firstname.lastname@example.org) and you are using a hosted analytics service, do you block the email ID from transfer to your hosted analytics service?
If you don’t, might this be a violation of privacy rules or your hosted analytics service agreement?
Food for thought.