"default" Keyword: An Interesting Statement

I noticed an interesting statement when skimming through Windows Workflow Foundation Hands-On Lab code, it looks like:

public int amount = default(System.Int32);

Now I feel a little bit not comfortable  with the "default" here. Look it up (from MSDN):

In generic classes and methods, one issue that arises is how to assign a default value to a parameterized type T when you do not know the following in advance:

• Whether T will be a reference type or a value type.

• If T is a value type, whether it will be a numeric value or a struct.

Given a variable t of a parameterized type T, the statement t = null is only valid if T is a reference type and t = 0 will only work for numeric value types but not for structs. The solution is to use the default keyword, which will return null for reference types and zero for numeric value types. For structs, it will return each member of the struct initialized to zero or null depending on whether they are value or reference types.

Now it starts to make sence why I don't feel very right here...

Copy a question from thescripts.com, maybe a good question for your next interview:

What's the difference among the following statements?

int x = default(int);
int x = 0;
int x = new int();