Why use ‘virtual’ for class properties in Entity Framework model definitions?

In the following blog: http://weblogs.asp.net/scottgu/archive/2010/07/16/code-first-development-with-entity-framework-4.aspx The blog contains the following code sample: public class Dinner { public int DinnerID { get; set; } public string Title { get; set; } public DateTime EventDate { get; set; } public string Address { get; set; } public string HostedBy { get; set; } public virtual ICollection<RSVP> RSVPs … Read more