In Germany there is a law allowing targeted marketing to active customers under specific constraints, regulated by law (UWG §7).
These come with a wide recipient base, because no newsletter opt-in is needed an offer a high value business case.
Definition of UWG7 compliance:
only closely related products to purchases from last 12 months are eligible.
closely related is defined usually by (sub)category, category tree depth depends on customer feed and customer segment, so the legal category level will vary between customers.
What's required for Product Recs:
1) constraint on eligible products: category depth - Eligible products need to be from the same subcategory (level 2) as a bought product in the last 12 months. The appropriate category tree needs to be configurable per customer as it may vary.
2) more strategies to achieve appropriate conversion - currently, only new products from related categories are recommended. Desired strategies would be
Merchandised:
Best Trending (from purchased categories)
Bestseller by revenue (from purchased categories)
Personalized:
Newly discounted from viewing history (from purchased categories)
Recently viewed (from purchased categories)
Recommendations based on popular views (from purchased categories)
3) a hint that prioritizes more recent purchases over older purchases
Issue changed to: https://jira.sso.episerver.net/browse/PPER-2639
https://jira.sso.episerver.net/projects/PMOD/issues/PMOD-1387