I have spoken often about knowing your customers, but also be clear who your audience is when designing your advertising. A TV, radio, newspaper, twitter and facebook audience are ALL VERY different. Often I see people using one statement on all social media complete with hashtags and @addresses on facebook and LinkedIn. I also see the same print ad running in VERY different mediums or TV ads audio run as a radio commercial. While cost effective, you might be limiting the effectiveness of your ads by not speaking to your audience. Consider who watches, listens and reads the media before you commit your ad to air or print.