Payroll tax a point of contention for San Francisco startups

San Francisco has been home to innovative tech startups such as Twitter and Zynga — the gaming company behind hits “Farmville” and “Mafia Wars” — that have fueled the social media revolution. But now that those companies are growing at fast paces, keeping them in San Francisco has become harder than ever. “San Francisco is such a logical place for innovative companies to locate,” said Gabriel ...