https://techcrunch.com/2020/12/02/everyone-has-an-opinion-on-the-27-7b-slack-acquisition/

When the Salesforce-Slack deal was officially announced on Tuesday afternoon, and the number appeared, it was kind of hard to believe. Salesforce had shelled out more than $27 billion to buy Slack and bring it into the Salesforce family of products. The company sees a key missing piece in Slack, and that could explain why it was willing to spend such an astonishing amount of money to get it.

With Slack, Salesforce now has what CEO Marc Benioff called the interface to everything, something he says that the company has thought about for years. In 2010, they tried building it themselves with Chatter, a social tool that never really caught on in a big way. With Slack they finally have it.