You've talked alot about Serializable e.g. Declaring the UDT as Serializable allows the UDT to be Serialized. Well ur, yeah, obviously! But what does that mean? What can you do with a serialized UDT that you can't do with a non-serialized UDT? This needs expanding on!
Other than that, not a bad article. A nice introduction.
-Jamie
Jamie Thomson
http://sqlblog.com/blogs/jamie_thomson