Personal privacy is something not to be taken lightly in Japan. I once had been working with a colleague for several months and casually asked about his weekend. You could almost see the dark clouds racing from the horizon. Whether it had been particularly awful I'll never know as he quietly but firmly replied that was "personal". Fair enough and one peculiar encounter a common trait it does not make. But when soon after I heard whispering one morning I asked the cause to which I was informed they thought the lady on reception may have got married. But no one was sure.
Given the choice of revealing a personal mobile number to the world or carrying two phones, one personal, one business, people in Japan will almost exclusively opt to carry the second device. And here it has to be said that I've been listing my personal number on my business card for over twenty years and I'm at a total loss as to if it has ever resulted in an unwanted call. However, I've even had my assistant once refuse to provide her own number and I had to swear on the graves of my forebears that I would only use it in dire emergencies of biblical proportions before she would give it up.
Once one of my staff tweeted (somewhat disparagingly) about a famous athlete arriving in our store. The Twittersphere exploded and within a matter of hours she was being i-mobbed, people even tweeting her home address and trolling her with abuse. We were actually quite concerned for her safety and took action as best we could. And so here in Japan, where the police won't actually do anything until you've already been clubbed senseless by a reported stalker, maintaining a strict Chinese Wall between personal and public is something of a national obsession. I still wouldn't mind knowing what the guy had been up to over the weekend though. He really did look guilty.