Plaxo is an online address book and social networking service founded by Napster co-founder Sean Parker and two Stanford engineering students, Todd Masonis and Cameron Ring. The company was named by David Weekly. Plaxo, based in Mountain View, California, is a subsidiary of cable television company Comcast.

Qubrit is a social networking website launched in April 2010 and owned by Qubrit Ltd. Qubrit provides virtual business cards services and contact management. Users can add and exchange their business cards with co-workers, friends, receive messages and updates from other people's profiles. The main feature of Qubrit is that other user's business cards, containing their emails, phones, addresses and links to their social networks as well as their virtual portfolios are constantly updated. By exchanging virtual business cards, users constantly have up-to-date information about each other. The website's name streams from the name of qubit (a quantum bit).

Visiting card:

Visiting cards became an indispensable tool of etiquette, with sophisticated rules governing their use. The essential convention was that one person would not expect to see another person in her own home (unless invited or introduced) without first leaving his visiting card for the person at her home. Upon leaving the card, he would not expect to be admitted at first, but might receive a card at his own home in response. This would serve as a signal that a personal visit and meeting at home would not be unwelcome. On the other hand, if no card were forthcoming in return, or if a card were sent in an envelope, a personal visit was thereby discouraged. As an adoption from French and English etiquette, visiting cards became common amongst the aristocracy of Europe, and also in the United States. The whole procedure depended upon there being servants to open the door and receive the cards and it was, therefore, confined to the social classes which employed servants.Some visiting cards included refined engraved ornaments, embossed lettering, and fantastic coats of arms. However, the standard form visiting card in the 19th century in the United Kingdom was a plain card with nothing more than the bearer's name on it. Sometimes the name of a gentlemen's club might be added, but addresses were not otherwise included. Visiting cards were kept in highly decorated card cases.The visiting card is no longer the universal feature of upper middle class and upper class life that it once was in Europe and North America. Much more common is the business card, in which contact details, including address and telephone number, are essential. This has led to the inclusion of such details even on modern domestic visiting cards, a practice endorsed by modern books of etiquette, such as Debrett's New Etiquette.