When the America Godzilla was released it 1998,
it was a triumph of marketing over plot, acting, special effects and audience enjoyment.
"Clovefield" has broken records with a 47 million dollar box office gross. Sequels and toys have been announced. http://www.hasbrotoyshop.com/ProductsByBrand.htm?BR=863&ID=21030
Here are a couple of theories;
1. Like "The Blair Witch Project," the narrative is told from the point of view of the victims.
2. The Monsters are unseen and are fast.
3. A giant Monster is only revealed partially.
4. Like "Alien," this Monster breeds.
5. The Monster's children infects humans and makes them look ugly.
6. The Monster uses humans as their hosts.
7. Footsteps of the Monster are heard before it wrecks havoc upon New York City.