A few weeks ago Yammer walked away with top honors at TechCrunch 50. I'd been hearing about it, so last week I went over and signed up. I'm really liking it.
Yammer is Twitter for work. The first person to sign up using an email from a particular domain establishes a sandbox for yammers from people in that domain. Since I signed up using my kynetx.com email, Yammer automatically created a domain for Kynetx and made me an administrator. Very low friction.
I sent out invites and soon had the whole Kynetx gang yammering away about work. Only people within your domain (i.e. those with emails you control) can see what the others are saying. Yammer has a Adobe Air client that makes keeping up with what folks are saying easy (you can also use the Web). In addition, Yammer has a number of features that are geared for business like the ability to input and display detailed contact info and organizational information as a crude social network.
We've been using Yammer for a week now and everyone feels it's been a good addition to our communications patterns. This is especially true with a distributed workforce like we have now.
So what of Twitter? Most of us still use Twitter too. Twitter is my public space. Yammer is my work space. That separation has real value and enables conversations and uses for Yammer that just wouldn't happen on Twitter.
We've made real decisions over Yammer that would have previously taken a phone call or email chain. Generally people are pleased with the connectivity it provides. For us, Yammer is a keeper.