Instant Messaging challenges abound on a global project. There is no one solution that works right for all. Whether it is a corporate firewall or the Great Firewall, or just an unwavering commitment to that one specific tool you have always used, somebody ain't gonna be happy.
After a great deal of back and forth on this, if you want to contact someone in a hurry, use WeChat. Just about everyone will be inconvenienced in some way, but no one should be completely blocked from being able to IM a colleague, which is the whole point.
WeChat will allow a simultaneous connection from your cell phone and one compute device. It has a Windows client, a Mac client and a web client available. Everything starts with the phone as the primary access point and much of the navigation is controlled by the use of QR codes (it has it's own built in reader, so you don't need to get one)
Once in search for the "ONAP Lobby" or ask someone that you think belongs to it to invite you. (LOOKING FOR A LIST OF VOLUNTEERS HERE)
IMPORTANT! The purpose of the ONAP Lobby IS NOT for conversations per se, it is primarily a way to ensure that you can easily search for the people you need to contact in one place. Most of the time the conversation will should be in a separate 1:1, or group chat, or your conferencing solution of choice.
Does WeChat Support bots? Nope.
Does WeChat support drag-n-drop? Yup
Does WeChat have a desktop client? Mac, Windows and a web version
Can I invite people? Any current member can invite someone by clicking on the “+” and the person you plan to add.
Can I remove someone? Only the owner of the group (Administrator) can remove members.