The website got some nice updates:
http://www.amityvillehorrormovie.com/
There is also clips of a psychic named Lorraine Warren. Said she had been in a lot of haunted houses and the Amityville house was the most haunted. She also tells some very interesting tails. Check out those clips on the site. Perhaps the house really was haunted? And maybe the Lutz's embellished a little? She is 100% positive sure the house made DeFeo kill his family.
Or it all could be just movie promotion stuff.