In ASP.NET MVC, I typically use <a href="http://lostechies.com/jimmybogard/2012/04/10/asp-net-web-api-mvc-viewmodels-and-formatters/">View Models along with the <a href="http://james.newtonking.com/json">Json.NET library to get JSON back to the client.  When I want some members to be omitted from serialization I will simply add the [JsonIgnore] attribute to the target property.  This works great for static omission but sometimes I come across the need to perform _conditional _(i.e. at runtime) omission.  To do this, you can use the largely undocumented [bool ShouldSerialize{MemberName}()] \approach.