No one has a problem sharing their address book as long as they know that it's being done and they approve. The rest of your comment doesn't really seem to fit, if people don't like what a company/app is doing they complain and eventually stop using it. You, as a developer, can choose to try and keep them by meeting their needs or not. The problem is that apps have been doing things that the customer didn't know or approve of - the fault is clearly on the developer in that case. In general, be honest and let your customer know why you need what you need, e.g. to provide a better service, to serve better ads, to resell to 3rd parties etc.