If there are blisteringly strong penalties to holding and trading in personal data, the incentives to do so will largely disappear. Unfortunately, statutory regimes, particularly in the United States, seem to be going in the opposite direction.
With the ability to seek out and purge disclosed data, at least some of the damage can be mitigated. Considering that there is far too much information for humans to ever process but a small portion of it, that might actually be sufficient -- we won't be needing the Men in Black eraser pens.