It is from MICROSOFT.
My first reaction was to think of a tool used in food recuperation.
Yes, it is spelt as Yammer and is in the dictionary.
One definition:
Yammer is a social networking tool to openly connect and engage across your organization.
Already I am getting sleepy...

YAMMER | meaning in the Cambridge English Dictionary
[Search DOMAIN dictionary.cambridge.org/dictionary/english/yammer] https://dictionary.cambridge.org/dictionary/english/yammer
yammer definition: to talk continuously for a long time in a way that is annoying to other PEOPLE: . Learn more.


We have Yammer in our organisation. It is a really good way for idiots to post jokes or pictures of their office cake COMPETITION. We all ignore it.Salmon Trout,
Thanks for the insight.
Now I can understand why it is needed in a large organization.
If we had a Yammer section here on CH. I might be able  to Yammer some. 
You already do...without Yammer...If you susbscribe to our organisation's Yammer, you get a lot of email notifications of new content like "Joanne Bigglethorpe has posted an update on Yammer that may help you in your work! Click here!" and if you click there, you find out that some person in an office 400 miles away, that you never heard of, has had a *censored* baby, or has taken a picture of her dog with a hat on, or has discovered how to make Microsoft Excel add two numbers, or wants to tell everyone that it's World BANANA Day. Totally unmoderated. So we block them.
Salmon Trout,
Oh, I might already have that...
It's called FACEBOOK!