Why is Salesforce.com building a social network?

"Welcome to the social enterprise," greets the homepage of Salesforce.com. It seems a peculiar direction to take a company that built its bread an butter business on salesforce automation tools. It's peculiar until you understand how Salesforce makes money.

Salesforce charges companies on a per user basis. Initially its salesforce automation tools meant the company was chasing after a market size constrained in size by the number of salespeople on the planet. Pretty quickly they realized that they were in the customer relationship management (CRM) business. With this angle, the same tool could be used by customer support staff, service staff - any person in a company that interacted with a client. The shift in thinking from salesforce automation tool to CRM changed the size of market - the pool of all the possible people that could pay for and use their software.

From the CRM perspective, the market size is now constrained to every employee who works with an outside party. How can Salesforce get even more people on to its platform - charge even more people - potentially get every single employee in an organization on to its platform, so that the organization pays a charge for every single employee?

What about an internal collaboration tool for employees - a tool that is as addictive as Facebook, but just for your organization? With a company's salesforce already using this platform, and perhaps even customer support and other departments, what happens when all these teams start using Salesforce's new social networking, Chatter? Pretty soon everyone else starts to feel left out.