To clarify, the author is listing features that differentiate Yammer from twitter, which it started out as being most similar to (but a private, company / organ

To clarify, the author is listing features that differentiate Yammer from twitter, which it started out as being most similar to (but a private, company / organization internal usage version of). Unlike email, Yammer or other twitter-like platforms are ambient, one-to-many without demanding each person's attention, and length-limited. It's easy to put a message out without being interruptive, and get attention to it / responses from whoever's available. I find it pretty valuable.