BAN BARKAWI USING social media, hundreds of Lebanese have offered shelter to strangers displaced by a devastating blast, which Beirut's governor said may have left 250,000 people homeless. Tuesday evening's explosion in port warehouses storing explosive material was the most powerful ever to rip through the capital, killing some 110 people, injuring about 4,000 and tearing the facades off buildings and overturning cars. Using the hashtag #OurHomesAreOpen in Arabic and English, social media users have freely offered up spare beds and empty properties to victims, providing their names, phone numbers and details on the size and location of the accommodation.…