Approximately 70% of CBS's revenue is earned through advertising sales which are particularly vulnerable to economic downturns. Furthermore, many of CBS's business segments including television and radio broadcasting are undergoing a secular decline in advertising because of the rise of Internet advertising- as a result, CBS's revenue may decline up to 25% this year. In Q4 2008, CBS's revenue declined by 6% following significant drops in advertising expenditures in its television, radio, and outdoor segments. Additionally, automotive ads typically account for about 30% of CBS's advertising revenue. Therefore, the turmoil in the automotive industry will most likely spill over into CBS's advertising revenue for at least the next year.
Trends show an increase in time shift programming (i.e. allows for fast forward) and this may decrease advertisers’ willingness to purchase advertising. Since advertisers may start shifting away from typical cable broadcasting, CBS must find new innovative ways to provide advertising or face significant drops in revenue.