[mtrimpe]

You could also consider having a limit of 1 or 2 private projects and make all the others public.

If you give public mockups a publicly accessible page and create a base representation that is indexable by Google, it might be an interesting source of additional incoming traffic (and leaves you open to become something like SpeakerDeck for Mockups.)

[moqups]

We decided to avoid publishing an indexable listing of public projects so we can protect the privacy of our users at least to the extent where they don't publish the unique, indecipherable link themselves ("Available to anyone who knows the link"). We think it's the most ethical approach for handling this situation.