Great to see you can now add non-members of a Team to a channel meeting by adding their email address in the channel meeting invite, or sending them the "copy join info" link once a channel meeting has started.
Is there a similar feature in the works for the conversations feed?
Use Case >> I'm having a channel conversation about a new Marketing Strategy which has brought up a technology question, so we wish to ask an IT expert a question to help us out. This IT expert is not a member of our Team (and we don't want them to be, and neither do they). So all we want to do is @mention them into this one conversation (they won't see anything in the channel, except this one conversation)
You can do this in Yammer, as Yammer allows you to participate in groups you have not joined.
...but at the moment in Teams, I have to switch to another tool to ask that IT person a question - which is quite a counter behaviour to one of the pillars of Teams ie. the "Hub"
There is always chat tab for this. But meetings should be treated like group chat and let anyone on it participate in chat. Then once the call is done you can always move those chat messages into the channel chat, or they could "sync" channel chat with a group chat during the call to get around the whole, so and so in the call needs access to the team to do chats etc. Then you could even @mention in the chat since that's supported. Just have that call sync that chat into the channel real time or something.