Microsoft’s $1.2 billion purchase of enterprise social tool Yammer caught many by surprise. Three quarters later, Microsoft is publicly trumpeting the price that it paid, right next to performance metrics for its new subsidiary. The implication is simple: Yammer was a good buy.

Today in a blog post, Microsoft detailed that in its fiscal third quarter – the most recent quarter – Yammer grew its sales by 259% year over year. In the quarter, its best regarding “user engagement,” Yammer added 312 new clients.

Juan Carlos Perez at CITEworld clarified with Microsoft, regarding the sales metric. He reports that: “[Microsoft] specified that to calculate the revenue spike, Microsoft considered only sales of standalone Yammer licenses, and left out revenue coming in from Enterprise Agreement volume licensing deals involving the ESN product.”

Put another way, the above 259% growth figure only applied to Yammer, and nothing external to it.

It’s mildly frustrating that Microsoft will only report a percentage-ratio figure regarding sales, but it isn’t out of character for the firm. In its most recent quarterly report, Microsoft, by way of a single example, detailed that Windows Phone revenue rose by $249 million. But it declined to disclose the aggregate number, only releasing the increase.

Amazon is infamous for releasing ratio data as well.

Yammer integration across Microsoft enterprise and corporate products, particularly SharePoint remains nascent, it should be noted. A final point: Microsot is exceptionally fond of announcing when a new business segment reaches a run rate of $1 billion per year. That breaks down to $250 million per quarter. As it hasn’t said as much about Yammer, we can assume that it hasn’t reached that size. That gives you a better comprehension of its size.

Top Image Credit: Håkan Dahlström