Should You "Spy" on Employees Through Social Networking Sites?

We are all aware that someone can Google us (this blog is the #1 hit for me!) if we apply for a job, or even if we already work somewhere. But, there are lots of things Google doesn't index, like profiles on sites that require registration.

A friend recently told me that he finally tried one of the social networking sites that people keep telling him about. He did a few searches to see who he might know on the site, and he found several people that worked for him. Then it got really interesting. The profiles on this site include information about sexual orientation, drug and alcohol consumption, and a space to list how you feel about your job. These are optional to fill in, of course, but many people do nonetheless. My friend found some shocking information on the profiles of people he knew.

Some would argue that you shouldn't put information in a profile anywhere, on any site, that you wouldn't want anyone and everyone to know. That's not the issue here. What I want to know is this…Is it ethical, as a manager, to subscribe to these sites with the primary intention of gaining information about employees and/or job candidates? Will we ever see a business model in which a company pays for access to profiles from membership sites of all kinds, sucks in that data, correlates it with real people the best it can, and sells it along with background checks etc.?

This would have been a good question for me to ask on the ethics exam in my Information Systems course.