Cory Doctorow, of Boing Boing fame, has an opinion piece in The Guardian: Cory Doctorow: why personal data is like nuclear waste Technology guardian.co.uk
We should treat personal electronic data with the same care and respect as weapons-grade plutonium - it is dangerous, long-lasting and once it has leaked there's no getting it back...
I'm not sure that nuclear waste is the best analogy. In speaking on the topic, I usually liken personal information to heating oil. Many businesses need oil to operate. Either it is the raison d'etre of the business or it is just one of those things that supports the business. Whatever the case, it needs to be carefully stored or it can leak out and cause a huge, expensive mess. And personal information, like oil, should only be kept around while it is needed. If you don't need it, dispose of it carefully. Personal information that is no longer needed is akin to an underground oil tank: get rid of it (safely) as soon as you can.
No responsible business would allow employees to transport oil in inappropriate containers. The same should apply to personal information.
Personal information is an asset, but a dangerous one: if spilled, can cause a disastrous mess.