Amazon (AMZN)'s advertising business is approaching $50 billion in annual sales, but it may still be early days for the division, according to Wedbush analysts who raised their target price for Amazon stock.Amazon "is well positioned to continue taking share of global digital advertising spending over a multi-year period," Wedbush analyst Scott Devitt told clients in a Wednesday note. The tech giant is on pace for$46.5 billion in advertising revenue this year, he added. Wedbush estimates Amazon's ad sales ...