First, I would focus on privacy. Second, on specific photo tools that Facebook isn't going to offer. Make sure that people can easily sign up during a party or

First, I would focus on privacy. Second, on specific photo tools that Facebook isn't going to offer. Make sure that people can easily sign up during a party or an event at which a group of people is taking pictures and want to share them (afterwards). Make 'joining' an album free and let the 'album owner' pay.