Many times you want to link from your web page to an external source or related page, but you have multiple such sources or related pages connected to the same word or phrase.
It’s easy to find all the shops in the category that might stock the item you are looking for. But then you have to visit every store only to find out many don’t have the item you are looking for in stock at the moment.
Have an item based search app or website that allows you to browse at a much more granular level like “10 years old swim trunk.” It will show you all the items currently in stock, which shop you can get it and at what price.
So you can test your email variations (subject lines, CTAs, etc.) on real people with similar demographics that are not on your list.
Aggregate people who are willing to receive test emails from a wide variety of demographics. The marketer can select a group from these people based on demographics and psychographics and do an A/B or multi-variant test of his emails to this group.