We have 30 people across 9 countries and several teams who have very limited real time cross over. We don't send internal emails. We use: Slack for asynchronous discussion. If someone posts something in Slack they should expect a response within 1-2 days. Salesforce chatter for operational discussion. Comments on here should get answered within 1 work day. Skype chat for real time chat. This should get answered asap (let's say 15 minutes). Zoom for all meetings.