Four top execs from Yammer - sold to Microsoft for $1.2bn in 2012 - have left the company to head up a voice, video and content collaboration firm.
Fuzebox has named ex-Yammer chief customer officer (CCO) David Obrand as its CEO, former Yammer sales leader Mary Pecka as CCO, ex-Yammer Georg Ell as VP of Europe, the Middle East and Africa and ex-Yammer finance exec Jonathan Grant as VP offinance.
Fuzebox, which enables people to communicate and work together over different locations and devices, also announced $26m in series B funding led by Hermes Growth Partners as it launches a service allowing potential customers to "experience the value" of the software before subscribing.
Obrand is credited with playing an instrumental role in Yammer's growth which led to its takeover by Microsoft, and his new role will take him into direct competition with Microsoft's Lync, as well as Cisco WebEx and Citrix GoToMeeting.
"I am thrilled to join FuzeBox at such a pivotal time in its growth," he said. "We will use the new capital to expand our technology leadership, drive viral freemium adoption, scale global sales and marketing, and build a world-class support organisation focused on customer success."
Ell told the Telegraph: "Leaving Yammer was just the right time for me. I'm very proud of everything we achieved, and all four of us left Microsoft on extremely good terms."
Board of directors member and partner at Hermes Growth Partners, Bobby Yerramilli-Rao, said: "We are excited to welcome David, Mary, Georg and Jonathan to the FuzeBox team.
"The funding reflects our confidence in their leadership and FuzeBox's success, product innovation and future potential."