CEO David Sacks says there are now 10,000 networks and 50,000 users just one week in. Yammer’s business model is to let people use the service for free, spreading it throughout the enterprise. When and if a company wants to take administrative control over the account, Yammer charges $1/user/month. Administrators can set access controls, such as IP controls and SSL.
The company already allows interaction with the service via the site, an AIR client, iPhone, Blackberry, IM, SMS and email. This evening they’ve also launched an API to allow third party developers to build Yammer into their applications.
Maybe it might start at one dollar a month but who knows what it might turn into, because by then your enterprise social network is in there hands. I have no idea why we're not running to Laconi.ca faster. Maybe because it will actually require someone to set it up, keep it running and administrate it?