The business card isn't the place to list every service you can possibly provide. Nor is it the place you tell the world that you're a web designer and run a mobile detailing company. Your business card is your chance to decide how someone will mentally categorize you without any outside influences. The moment you hand them your card they will decide who you are and how important, successful, and competent you are. Unlike your twitter feed where how many followers you have weigh in on how important they think you are. With your business card you decide how important you are in your field (list ways you can show your competence and importance). The quality and design of your business cards is in your control.