What is Pelagianism? Exploring Augustine's 14 Point Definition

In this live stream Warren gives a brief overview surrounding the build up to the conflict between Pelagius & Augustine; proceeding to detail the 14 point charge Augustine levied... answering the question "What is Pelagianism?"

Is Pelagianism simply a rejection of Original Sin, an acceptance of man's God given free will, or a denial that man doesn't need God or His grace? Does it have any grounding in reality? Or is this a boogeyman and invective used to abuse theological opponents without resorting to actually engage the arguments?