The first airing of Comedy Central’s Roast Of Justin Bieber was the No. 1 program on cable last night among the 18-49 demo, pulling a 3.3. The 10 PM insult-a-thon Comedy Central 2 logodrew 4.4 million total viewers and added 1.4 million in its repeat. The network said the show did best among the 18-24 crowd (5.8) and topped all of TV in a number of younger demos including 18-34, 18-24 and men and women of both age ranges. Another 420,000 folks dialed up the live stream, the cable net said today. It also was the most social show on all of TV, piling up more than 1.3 million mentions and dozens of roast-related trending topics in the U.S. and around the world.