There are 30 designs from which to choose, including the Web 1.0 version (containing your contact data), Web 2.0 version (with your personal tag cloud), or the Web 3.0 version (featuring the URL of your Ziki profile only). There is a simple-to-use online customization process which allows you to modify all of the data as well as upload a logo or image and change the colors/fonts.
I imagine it will likely appeal to small business owners/sole proprietors/independent consultants (i.e., those most likely to use a self-serve online printer and willing to use Ziki-branded cards).
But I've also seen more and more young people using these types of calling cards (Flickr has some, too) to exchange personal information with new contacts (rather than the staid old business card). And the nice thing about Ziki is that can aggregate all of your online content in one place, serving as a portal into your other sites or networks.
The physical card is a nice strategy for Ziki, too, as it continues refining its positioning as a "people search engine," giving its members one more way to be found.
I'm curious to know how many people actually take them up on the offer.