My most recent hire is from a different country. We invited him for a face to face interview before giving an offer. He is handing a notice to his currently employer and hasn't started working for us yet.
He comes off as overly familiar and somewhat an online stalker. So far he did the following:
Searched for my photos online. He didn't stop at just seeing how I look like. He went deeper to see how tall I am, ...etc. He managed to find photos of me that I cannot find myself.
Found my personal email address and added me on chat. For the record my email account cannot be found by search. He must have done some very intense detective work to find it.
Found my personal Skype account and added me.
Added me on Facebook, Twitter, Google+, ...etc
He did similar things to the other interviewers as well: Personal emails, facebook, watching/reading anything to do with them online.
He was very friendly and eager but
otherwise normal nothing else stood out when we met him face to face. He was very open about researching us online and finding as much as possible. He is very smart and an extremely good fit for the position. It took us a long time to find someone with the skills we need.
How best to deal with him as his direct manager?
I talked to him according to @JoeStrazzere advice. He seemed to understand. I really feel that some answers took this too far. It was more of an overly friendly and familiar behavior than anything else. Strange, yes, but not a red flag in my opinion.