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.