Shriek

The Wall Street Journal guesses why the third parts of three big franchises fared less than well:

May's big blockbuster "threequels" -- "Spider-Man 3," "Shrek the Third" and "Pirates of the Caribbean: At World's End" -- are all expected to fall short of the last installments in those series at the domestic box office... The domestic performance of the films may be a sign that audiences are growing fatigued with overly familiar offerings.

I've got a theory: it's not the familiarity, it's the lack of newness.