I may or may not be suprising that i haven't covered every kind of Digital business card available today.
The following cannot be directly categorized under the previous categories (although it can be a subcategory under phone business cards and internet business card.) That aside, these subcategories are already widely used so it is really worth knowing about them.
Twitter Business Cards
Twitter did not start too long ago yet everybody is using them now and necessarily so, twitter business cards have also started gaining popularity in use.
Blogger business cards
Whether you use wordpress or Blogger or other online blogging platform,
Online ID Cards
Although they are called ID Cards, i think they also serve the purpose of a business card.
http://bloggerstop.net/2010/07/3-blogger-business-card-templates-your.html
