Twitter's (TWTR -1.3%) first 10-K filing reveals the company's "ad engagements" rose 74% Q/Q and over 6x Y/Y in Q4. At the same time, this surge in ad impressions/inventory led the company's average cost per engagement to fall 18% Q/Q and 69% Y/Y.
Twitter notes the launch of its promoted tweet/trend/account ad products on mobile served to grow inventory, as did their launch in new international markets. The company unveiled a slew of new ad products in Q4, including ones specifically aimed at TV viewers and mobile app users.
Also disclosed: Twitter's U.S. ad revenue per 1K Timeline views is still more than 6x international levels ($3.80 vs. $0.60). The U.S. figure rose 48% Q/Q, and the international figure 67%. This gap is the reason international sales accounted for only 27% of Q4 revenue, even though Twitter's international active user base is more than 3x as large as its U.S. base.