It's amazing that people still toss out bare hard drives in the trash... sure the HDDs might have been faulty, or just too small and too old, but do they seriously expect the data to be "gone"?
Recently PCSTATS happened across a bag full of hard drives out at the curb in front of an office. All were labeled "broken", of course none were non-functioning.
Using simple tools, we were able to open up password protected payroll and staff address records, and many other documents. Thankfully, no SIN numbers were stored there.
Bottom line, physically destroy a hard drive's platters before tossing it out. If you don't, the data it once contained is up grabs to whomever wants it.
On a related note, Vernontech have a cool hard drive crusher that does the job a hammer sometimes can't. Follow the link to watch a video of it in action.