Beware of Facebook or any social networking site. The information they get from you belongs to them and not to you, and they can use it any way they want.
Yahoo gave the Chinese-worse-than-communist government all the information they had on dissidents – names, messages, addresses, phone numbers, associations – supposedly because Chinese law said they had to. I suspect it had a lot more to do with getting money by winning more of the Chinese market.
If you do staffing, be especially careful of any information you put on a social network. Keep your candidates and your own damn information private. The last thing you want to do is post a job to Monster that attracts candidates on a public site where they can get poached by other recruiters.
Staffing software should reinforce privacy. Applicant tracking systems suck in part because by definition they expose the privacy of the hiring manager/candidate relationship to a vast audience.
Stay-tuned for a product announcement here on recruitment software that has privacy built-in.