Ranked in these QuestionsQuestion Ranking
Pro A complete social network for business
Yammer works like a typical social network with status updates, comments, file sharing, groups, etc.
Pro User interface is modelled after Facebook
To make it easier to learn for new users and increase adoption.
Pro Hashtag support
Hashtags help organize projects and parts of projects easily. Great for getting an overview of a specific subject and seeing if something's missed.