Employees tend to have at least one of four goals when they use social networks, according to Amy Shuen, author of Web 2.0: A Strategy Guide. The first two are common, she says; the second two are more cutting-edge.

1. Quick access to knowledge, know-how and "know-who." In their profiles, people can list skills, expertise and experience, as well as previous employers and people they know. As with LinkedIn, this helps simplify the job of locating people with the knowledge they need. "It's a way of leapfrogging quickly through several degrees of separation to find out who knows something on a topic that's of importance to you," Shuen says. This is particularly useful inside multidivisional and multinational organizations, she says.

2. Expansion of social connections and broadening of affiliations. This is the Facebook model, Shuen says, in which the goal is to get to know people better online by interacting with them and keeping up with their personal information. "It's about decreasing your social distance virtually," Shuen explains.

3. Self-branding and expression of a personal digital identity and reputation. Before long, people get creative with their profiles and begin to think about how they want to be known in the company. This is along the lines of a Flickr account or a personal blog or Web page. "Web 2.0 is deeply changing the expectations of knowledge workers as to how they can build their own personal brand within a corporation, not just find knowledge they need or socialize," Shuen says.

4. Referrals/testimonials/benchmarking/RSS updating. On social networks, the viral distribution of knowledge becomes important. For instance, people want to know how many of their "friends" have recommended a video or have joined a community. And in turn, if they discover something cool, they want to spread the word. "This sense of benchmarking against others in social networking is different from anything we've seen before," Shuen says.