I have recently changed my daily process to include Yammer and the value add has been significant. Take for instance the release of Microsoft Dynamics CRM v2013 Rollup 1, Yammer post with link and discussions letting me know it was available.
If your company currently has YAMMER and you are not using it, you might want to reconsider. Timing is everything when it comes to accepting new and sometimes you just need to re-evaluate on an ongoing basis.