An interesting article on an important subject. I would have rated it 5 stars instead of 4 if it had gone further in explaining what might need to be done to fix potential problems - sadly it is not as simple as replacing = NULL with IS NULL.

ANSI_NULLS OFF behaviour is decidedly odd, and often counter-intuitive, no wonder Microsoft are keen to stop supporting it. I have an example of this type of weirdness pending as a Question of the Day (QotD) so I'll just say that one example of weirdness involves IN and NOT IN...