Q:

What's the most successful "scope" for a Trello board?

The inability to move cards between boards has pushed me into fragmenting my work.
For instance, I've found myself creating more boards for things like 

product 1
admin/general
website (mini-project)
marketing/promo
etc...

As one friend and Trello user pointed out that design is core to product development and shouldn't be a separate project (board) in Trello.  Given we can't currently move cards between Trello boards, I'm wondering if there's a better approach.
If I could move cards between boards, I could have a Design Ideas board with a progression of lists. The last list could be To Implement, and I could move cards from that list to the main product board.
But since that feature doesn't exist, I need to know what is the "sweet spot" for what should be a board and what should be a list? What has been the most successful for other users.

A:

I agree with your friend about not dividing up into separate boards by type of job.
With your examples such as 'Design ideas' etc, I think they really do fit naturally within different lists on the same Board. It's exactly the sort of usage that Joel demoed in multiple videos about Trello.
The only thing I can think of, to help manage very long lists, is to use Trello's Labels system to put categories on cards, and then use filtering. You should definitely give meaningful names to the default labels.
I wrote up some tips on how to use labels recently.
Having said that, fairly early on the Trello on Trello board got huge, and eventually they reduced the scope of it. So it's does seem to be a well-known problem.

