At the beginning of season 5 after Ben turned the wheel everybody started to jump through time. Now I have been re-watching season 5 and have been realizing that whenever they "jumped" they appeared at a critical point in the island's history. The first flash, the Nigerian drug plane crashes on the island. And in another shift the french raft lands on the island. and in the second to last shift they see a statue. And it could be when the black rock arrives when jacob and the other guy are sitting on a beach. so my theory is that when the island was jumping, it pulled in others to land on the island.