Although Cisco has a very strong position in the UC market, its strengths are mainly in UC of the past (on-premises deployments and telephony focused).
The acquisition of Broadsoft will help Cisco to better compete in the next generation cloud UC and team collaboration.
Overall a strong move of Cisco to help it compete with its rivals such as Microsoft and Slack.
WebRTC Usage Numbers are Hard to Quantify
A similar but more complex question arises for WebRTC. WebRTC is a lower level technology than WordPress. WordPress is more of a complete solution than WebRTC. WebRTC has a more permissive license (BSD for both the Google and Ericsson implementations) and there are good reasons to reuse sub-components of it for different purposes.