Following its announcement from Ignite 2021, Microsoft has started rolling out the capability to chat with external and personal accounts directly from your Teams work account, without switching tenants. The company says that the ability to do so is crucial in this hybrid era of work where you have to interact with various vendors and partners online, some of which may be small- to medium-sized businesses (SMBs) utilizing Teams personal accounts.
You can collaborate with external accounts by simply adding their email ID or phone number, and can even add them to group chats. An important point to note is that this is a two-way street, personal accounts can also invite work accounts for online interaction. As usual, if the person you're trying to reach out to does not have a Teams account, they will receive an email or an SMS asking them to sign up.
There are some administrative and user-controlled governance in this space as well. You can block external contacts, leave group chats with them, and decline external invitations too. External contacts can send you up to 10 messages, but if you do not accept their request, they won't be able to send you additional messages.
Naturally, IT admins have a degree of control over communication with external accounts too. Both inbound and outbound communication with accounts not managed by your organization can be disabled, and you can opt-out individual users by creating custom policies through PowerShell as well. By default, the configuration enables external communication so if this does not suit your organization, make sure to opt-out as soon as possible.
Microsoft has also put some protections in place given the nature of possible interactions with external accounts. This includes explicit opt-in in terms of accepting requests from external accounts, external badging, spam checks, message limits, and hiding of identifiers like a profile picture, among other things.
The bidirectional communication between work and personal or external accounts has started to roll out now, so keep an eye out for when it becomes available for your organization or personal account.