Now Playing: 11-06-13 Marketplace - TWTR tmrw

We often think of the stock market as the province of the machines. But in the Twitter IPO, the pivotal role is played by a human: the designated market maker, who will act as a conduit for all trading in Twitter shares. Marvel is diversifying its stable of superheroes with a new series featuring a teenage Muslim lead character. How much of a role do financial considerations play in creating a new superhero. Finally, Bart Chilton, known for quoting rock-and-roll lyrics in firebrand speeches, is leaving the Commodity Futures Trading Commission. His coming departure and other changes raise the specter that the regulator could soon be well short of its usual five commissioners.