― Professionals who want to avoid the clutter of the traditional Rolodex file have begun to explore the possibilities of online business cards. Some professionals give out cards with QR codes that can be read by most smart phones. These QR codes link to online business cards or portfolios. Other professionals are relying on business card apps, primarily on the iPhone and Android phones, to take care of their business networking needs. Five of the top business card apps are outlined below. .