External public social networks, such as Facebook, MySpace, LinkedIn and Friendster can be valuable sales, marketing and support tools for many organizations, due to the extensive network of users, organized into groups and communities. The Friend-of-a-Friend trust model that interconnects members of a social network is also useful as a conduit for product testimonials and referrals.

There are several ways an organization can benefit from using external public social networks. The following are examples of legitimate business usage of public social networks:

• Use of public social networks to create groups to support campus recruiting.
• Use of public social networks to create affinity groups to support product marketing (referral networks, testimonials, focus groups).
• Use of social networks for outreach purposes, especially by non-profit and social services organizations.
• Use of social networks to create custom network applications (a.k.a. plugins) for product and brand promotion or integration with a company’s own online services.