Advertising revenue at YouTube reflected the video giant’s continued momentum, rising 12% in the third quarter compared with the year-ago period. The haul of $8.92 billion in the period ended September 30 came as many ad sellers, particularly traditional media companies reliant on legacy TV, have been reporting flat or low-single-digit growth. Most media companies will be reporting quarterly numbers over the next two weeks, with YouTube now setting a high bar for ad growth. The performance of YouTube helpe ...