Even if it never makes any money, Twitter certainly does provide fabulous material for television spoofs.So far, Jon Stewart and Stephen Colbert have done several funny bits on Comedy Central, deftly mocking the microblogging service.And now, Conan O'Brien is doubling down with two skits so far dubbed "Twitter TRACKER" on "The Tonight Show."In them, a loudmouthed voice delivers pointless celebrity tweets, as a flock of cartoon Twitter birdies are murdered in various ingenious ways.