A Geeky Viewpoint

Get ready for the discussion.

The largest percentage drop from a major Marvel production from opening weekend to the movies second weekend is X-Men Origins: Wolverine at 69% (dropping from $85 to $26).

Several sites are predicting a 70% drop in ticket sales for The Amazing Spider-Man 2, one site (behind paywall) has suggested the movie should consider the second weekend a success if it his $25 million (74%).  

Historically bad Super-Hero movies (X-Men: Last Stand, Green Lantern) drop about 60 to 66%, the drop they are talking for TASM2 is almost unprecedented.  Harry Potter: The Deathly Hollows part 2 being the lone exception but as the 8th movie in a series people wanted to see it no spoilers before have a successful 12 week run.
On the flip side good Super-Hero Movies (Marvel's The Avengers, Batman Begins) tend to drop about 50%.