In brief, Nosto can’t give you legal counselling as you need to comply with your country’s legislation. Therefore we can only give you broad advise by describing how Nosto works.
2) If Nosto email features are enabled, communicate the opt-out possibility easily for the user (link is by default positioned on the bottom of an email sent by Nosto)
3) Sync email blacklists across multiple email marketing providers (ie. a person who opted-out of Newsletters should not receive any personalized retargeting emails)
Email-addresses are collected only to enable Nosto’s email features, hence mapping email and name details are only required if you want to utilize the email features. Leaving the email-detail out in the implementation is supported and perfectly fine.
One way to describe and communicate Nosto’s functionality to visitors on your website could be following: The purpose of the service [Nosto] is to display personalised product recommendations on-site, in emails and other mediums which make the shopping experience easier, more personal and enjoyable. However, do not add this to your website without consulting your legal department or lawyer first to make sure you comply with your local legislation.