As I have identified earlier there are two types of social networks:

• hard-linked networks, where users consciously select and build their network by hand-picking their friends.
• soft-linked networks, where users become part of a group depending on their activities.

Building the catalog and going through many different sites, I decided to add another dimension in identifying the networks. This time identification will be by type of activities:

• general purpose

General purpose networks, such as Facebook, MySpace

• professional

Networks targeted to professionals, LinkedIn, Viadeo

• targeted

Networks that are built for very targeted niche, such as Flixter or ParentsConnect