Well, if you'd like, check out http://youmixer.com and tell me what you would improve about it to make it viral. I'm working on another project right now, but I'm always curious how I could have made youmixer better.
You can just reply on here if you want to keep your anonymity.
I think you should change the logo, it looks a bit cheap.
From what I can see, anyone can contribute to a mix, this isn't desirable, if you can figure out a way of upvoting the best mixes, you might be onto a winner ...
mixes have two settings: visible_to and editable_by. Only mixes that are editable by everyone fall into the category you describe. People can choose "self", "friends" or "everyone" for any mix.
I think the problem is not the privacy, it's the complexity and lack of a good user flow... what was your experience going through it? Did you give up at a certain point? Was it kind of lame?
I feel like I need to get a web designer and just re-design the experience.