like most of the replies i've read i am going to straddle the fence on this one. i think that certainly for some there is a connection between their paticular BDSM proclivities and past abuse in child or early adulthood and that as slavelucy said this is not necessarily a bad thing and i am sure more then one has worked out their past in the safety of a BDSM relationship.
for me though the really interesting question is what draws so called "normal" people to. those that didn't have an abusive childhood and yet seek out what most would consider an extreme relationship. it's a question i am constantly asking myself and have honestly not come up with an answer for yet.