Hi Mark - I held an event in January for all our UK and global staff. Whilst the event was a live webcast we used Yammer (part of the MS 365 package) as our comms tool. Those attending were asked to download the app to their phones and take part on the day. Given it was our first event using this engagement tool - I think it went very well. In the future we will continue to monitor if this is successful or a one off.
Keeping your delegates and online viewers part of the event is a difficult one.