I also keep my work and personal life separate and can't be happier about it. I don't give my personal phone number, online names or even email to anyone just because we work together. It's not 100% rule, if I find mutual interest with a certain person I work with I might want to keep a contact outside of working hours, but these are exceptions, not the rule. I've been asked for my online identity few times during job interviews, but a polite response of "Sorry, I don't use my personal Facebook, Google+, Twitter etc. for business matters" did the trick and I was offered these positions anyway.