Australian newspaper 1st April Bill said, page-9

TLC I reckon the conversation went something like this:

Qi Lu: Bill, Satya I think we should buy Slack. Have you seen their user growth it's astonishing! What do you think? $8 Bil seems reasonable.

Bill & Satya: We bought SharePoint, Yammer, Lync and Skype plus we have 85% of Fortune 500's on our side. In short Qi we have almost all the tools we need now to crush Slack. We want true unification of communication for our business customers and our partnership with Thred can enable that. Let's focus on developing Skype for now while we integrate Thred on the quiet. Slack won't see us coming. Nobody will even remember who Slack was in 5 years time..

Qi Lu: Can I suggest we invest some of that $8Bil into Thred?

Bill & Satya: Knock yourself out. I'm off to golf.