Any organization with its own Web domain can set up a free, private social network with Chatter from Salesforce.com. Think of it as an internal Facebook for your company. The native iPad app--also free--extends desktop social collaboration to the tablet, enabling mobile access and collaboration across distributed teams. iPhone, Android, and BlackBerry smartphone apps deliver solid device interoperability. Chatter boasts around 80,000 businesses already using the platform. It's definitely an internal tool--users must have an email address on a single domain to be invited to connect. That limits sharing outside the company's virtual walls, but protects sensitive information far more than public social sites; none of the content is available to anyone beyond that domain, making collaboration confidential and secure. A few examples among the myriad potential uses: knowledge and work sharing, project management, team building, corporate news and communications, and idea generation and capture.