What effect does the virtual keyword have on entity properties in Entity Framework 5?

[intelx86]

I know that navigation properties in Entity Framework must have the virtual keyword in front of them or else EF can't do it's navigation property magic. But what effect does putting the virtual keyword in front of other properties have? I saw an example recently wherein every single property on the entity was declared with the virtual keyword. Does EF 5 really lazy load every property if I do that or am I missing something about how that works?