Our general thought process for why we have implemented features the way we have.

Boards & Tags

Boards are for overall themes and tags are for specification. An example of this is "Cars" and "Car Types". A board could be "Cars" and then some tags on a pin in that board would be "Mustang", "Sports Car", "Sudan", etc.

You would also like to share pins via "board" (designed only for a single user) instead of "tag" which designed for all users.