It allows you to link cards together is the simplest way to put it. If you have cards on separate boards that are related you can connect them. Here is some great information about related cards and examples of how to use it: https://blog.trello.com/related-cards-related-boards
Thank you for the reply.
Well, I'm gathering that leaving the cards unrelated means that only the one that had the attachment sees a connection to the other. By relating them, they both point to each other, but only insofar as the attachment is loaded...
Basically it's a helpful reference, but there is no deeper relationship between the two.
Is that correct?
After a decade of growing the most ubiquitous visual framework for productivity and project management, we are evolving Trello’s boards, lists, and cards model to bring context to content and help te...
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