There are reports that insiders with greviences helped the hackers. However, its stupid to suggest that sony did it to themselves. Burning bridges with actors and actresses by releasing their private info, social security numbers, and emails. Embarrassing themselves and loosing credibility. Lawsuits piling up. Investors unhappy. As for the movie, it might just break even when it could have done better. Estimated $40 million to make and only at most $17 million recouped so far.
if this was their stunt, it will be a costly one and no benefit. So, no, I don't think they did it themselves.
That's a terrible return for the costs of the hacking. They've been screwed, lost a lot of goodwill and trust from their partners and staff, had their future projects exposed and lost competitive advantage, and may be liable for fines and other penalties for some of the information that has got out.
These conspiracy theories are so poorly thought out and really expose a lack of critical thinking skills.
Well as my DH is a former Sony employee and potentially has had his private information leaked as a part of this (social security number, bank details etc...) it would be a bit bloody stupid of Sony to have done this deliberately. There's already at least 5 lawsuits (that I'm aware of) filed against Sony by employees/former employees for the negligence of having their information leaked. This is a headache that won't go away soon for Sony.