Do you want to send a gallery to your customer, but at the same time you don't want anyone else to see it? Or maybe you want to share some of your photos just with a specific group of friends? In another words – if you want to create a so called private gallery that only somebody will have access to, you can do that with JuicyFolio.
But instead of thinking of a password for such gallery, the link to the gallery will simply contain an automatically generated unique access code. So if you want to show your private gallery to someone, just send them the link with this code, which you can also change whenever you like (after that, the old code becomes invalid and a new code will be generated).
Finally, remember that even if you set up your gallery as private, you need to make sure that this gallery (as well as the folder it's in) is active. Because if you'd send a link to private gallery inside an inactive folder to someone, it's like giving them your flat keys even though the front door is still closed.
PS: You can also send a link to your private gallery by mail. All you need to do is to click on the envelope icon near the "Share on" text.