Yammer was initially created out of San Francisco back in 2008, with co-founder David Sacks formally launching the startup at a TechCrunch startup event. The company went on to raise north of $140 million in funding before Microsoft swooped in with its billion-dollar bid four years after its launch.
https://techcrunch.com/2023/02/14/microsoft-ditches-yammer-brand-and-goes-all-in-on-viva-engage/