(CRM) sees a market in helping companies get more social. on Tuesday is set to officially announce an extension of its Chatter social network for corporate customers.  The extension, called “Salesforce Communities,” is designed to help companies more socially interact with customers and others outside of their walls, says Doug Bewsher, senior vice president of Salesforce Chatter.

Chatter, which released in 2010, is designed to help companies use online social networking to work more productively with their employees in departments and offices worldwide.  Now comes Salesforce Communities, though Salesforce isn’t yet saying whether all of it will be fee-based.  Communities users don’t have to be Chatter users.  The company says it has more than 150,000 companies and organizations using Chatter, but it won’t say how many pay for it, nor has it ever disclosed any revenue figures for Chatter.