Mark Knoller lists top 10 reasons David Letterman is retiring
http://twitter.com/#!/markknoller/status/451838586846208000 Now that David Letterman is retiring, there’s going to be no end to the “Top 10 reasons David Letterman is retiring” jokes. Credit CBS News’ Mark Knoller for being one of the very first. Let’s have a look. 10. Running out of stupid pet tricks. 9. Chris Christie will be thin by then. 8. […]