Sony must have a huge amount of confidence in its Spidey reboot, The Amazing Spider-man, as while that movie doesn't arrive until July 2012, the studio has already pencilled in a release date for the sequel. Of course that doesn't commit them to make the movie, but as an unname executive told Deadline, "I think it speaks volumes about our confidence in what we are seeing on the new film and our desire to move quickly on the next installment."
It also speaks volumes about how highly coveted key release weekends are in the summer, as by snapping up May 2nd 2014 almost three years ahead, Sony is basically trying to ensure nobody gets in there first.
Things may change, as if The Amazing Spider-man is an amazing flop, Sony may call the whole thing off (although it would be rather embarassing, considering their confidence now), but it does appear Andrew Garfield will be getting back in his Spidey suit very soon.