Has the same meaning as crapload, and occurs in three circumstances:
1) As a typo.
2) As a euphemism, as "carp" is not the least bit vulgar.
3) An intentional mockery/parody of the typo, similar in some respects to zomg.
Person 1: How was work?
Person 2: ZOMG! WE HAD A CARPLOAD OF STUFF TO MOVE!