To me, legibility and simplicity makes a business card effective.
This video shows what my new business card looks like.
Design: Black text on white matte card
Front reads: WEB SERIES NETWORK (this is our official logo)
Back reads: Rich Mbariket, Publisher, WEBSERIESNETWORK.COM | email@example.com
I omitted my phone number because the majority of my first-time contacts is by email followed by a phone call (this might not work for you).
Summary: This business card clearly promotes WSN, who I am, what I do, our website, and how to get a hold of me. It's legible and simple. To me, that's what makes a business card effective.
My question to you: What makes a business card effective?