Yammer -- perhaps the most well-known of enterprise microblogging tools -- is driving CIOs crazy.
I'm not referring here to Yammer's now famous "freemium" approach of getting your colleagues hooked on a free version and then upselling a more enterprisey edition. The real problem is this: employees signing up by virtue of having an enterprise email address believe that the free version of Yammer is an enterprise-sanctioned and perhaps even enterprise-managed solution.
This is of course a complete delusion, albeit a totally understandable one.
As subscribers to our Enterprise Collaboration and Social Software research know, Yammer's free version is a legal conundrum for the typical large enterprise. In discussions with senior leaders from among our enterprise subscribers, a recurrent theme has emerged about the constant efforts they must take to educate colleagues about the platform.
Savvier enterprises whose employees have taken to the free version emphasize that their public social media policies apply to Yammer, rather than their internal collaboration policies. That means, for example, that you shouldn't share sensitive data or documents via that channel. Busy employees may not always ingest that message. And at a time when many industry gurus don't recognize the difference between external social media and internal social networking, you can understand why some of your employees may not grasp the nuances either.
At the same time, we don't counsel our subscribers to kill off Yammer eruptions either. Enterprise social networking is hard enough to nurture without suffocating it in the crib. (On the other hand many Yammer experiments end up suffocating on their own for some very specific reasons, but that's another story...)
You need to understand the implications of the free version, and do what you can and should do to mitigate risks until you come up with a sanctioned, supported alternative. That alternative might well include licensing the paid version of Yammer, though in the event, you'll want to review your agreement very closely, since like many cloud providers, Yammer's enterprise edition SLA isn't so hot either.
Other collaboration and social computing providers are watching the Yammer model closely. The more free services the get targeted at enterprise employees, the more you need to educate about acceptable use. Better yet, devise a roadmap to get out in front of those needs. Let us know if we can help.