Harry potter and the half blood prince delayed had affected Hollywood

So far in the Harry potter series, five movies had been released, "Harry Potter and the Half-Blood Prince" is the sixth one. This flim supposed to be released by today, it's a good date for releasing the movie because of a week before Thanksgiving day

But the Warner Bros has planned to released by next summer,this cause the potter fans anxious,Because of this thing other movie studios are excited.
One of the key thing in the Hollywood is movie releasing date.Earlier this year the another movie named "The Dark Knight"released by Warner Bros is one of the most successful movies ever.The studio were happy with one blockbuster this year, it want to try next year so they postponed the releasing date of Harry Potter and the Half-Blood Prince to July 17, 2009