For those of you who commented on my private shelf at GoodReads question here, I have an answer. I read the manual and finally sent an email asking. The nice lady who responded said that no, at this point there is no way to make a bookshelf private, but that they are aware that people want them and that it may be coming in the future.
So, there we have it.
I was pleased that they are considering it (provided that it is true and they weren't just being polite). Maybe, if people are interested in private shelves, we should all just email them and express our desires. Maybe that will help us get the future here sooner. Or not. Whatever.