Spotify saw a surge in users and advertising revenue in the fourth quarter of 2021, the company said on Wednesday, driven by strong promotional campaign performance. For the fourth quarter, Spotify reported (pdf) 406 million monthly active users, up 18 percent year on year and at the high end of the company’s guidance range. Premium Subscribers, or those who pay, grew 16 percent year on year to 180 million in the fourth quarter, which the company said was led by “strong promotional campaign performance.” Revenue from subscriptions grew 22 percent to 2.295 billion euros (roughly $2.6 billion), while Ad-Supported revenue shot up 40 percent to 394 million euros ($445 million). Ad-Supported Revenue reached a record 15 percent of total revenue during the quarter, the company said. Spotify also said it has 3.6 million podcasts available on its service, up from 3.2 million in the previous quarter. In all for the quarter ended Dec. 31, …