The prevailing media narrative is that location-based mobile advertising is intrusive or downright creepy, Alexandre Mars writes. But that point of view is best left in the past -- a new wave of mobile apps make location-sharing incredibly useful, giving users every reason to gladly share location data with marketers. "[Y]es, it's Big Brother time. ... My bet is that, like me, you may find that Big Brother is now a very welcome friend at Starbucks, on your commute, when you shop and at home," Mars predicts.