Marc Benioff’s own words say that user trust and control remain paramount. 

"Our customers’ data belongs to them, it’s their data"  and pointedly asked, "Where is this data going when I am using my LLM... These LLMs are hungry for our data"  - underscoring that we can’t let Slack messages become AI fodder without consent. Benioff puts trust above all ("Remember, trust is our number one value" ...this is on salesforce.com! ), even tweeting that the "most important thing" about Salesforce’s AI is making it 'trusted & ethical & responsible" because “it’s only all about trust for our customers".

Read 2018 Marc vs 2025... https://www.salesforce.com/news/stories/salesforce-ceo-marc-benioff-calls-for-national-privacy-law/

Slack message data should never feed any AI (analysis, summarization, or training) without user consent; AI features must be opt-in by default; any AI training or third-party access stays off unless explicitly enabled; every AI interaction is transparently logged; and workspace owners need a permanent kill-switch to disable AI entirely. Technically, can this be achieved easily? - for example a permission bitfield on each message object and scoped API tokens that enforce it -  baking a “trust layer” into Slack’s architecture.

Slack was founded on Stewart Butterfield’s belief that ‘we should be open and interoperate with our data’ — a philosophy he said ‘resonated with me’ and rooted in the early internet’s ideals... Full quote: "I related to the whole hippie, acid-test confluence of the early Internet. The idea that we should be open and interoperate with our data resonated with me" (Wired, 2014).

Can it be more clear? It wasn't meant to be slurped into Salesforce. Slack message data must never be analyzed, summarized, or used for AI training without user opt-in. Consent should be granular — per-message permission bits, enforceable through token-scoped APIs. Workspace owners need a permanent kill-switch for AI, and all AI activity must be logged, revocable, and off by default. Anything less breaks from Slack’s founding ethos and turns data interoperability into quiet surveillance and Salesforce owning all your Slack message data.

As I did some research today, no not AI, I found buildingslack.com - and emailed the pair who are documenting Slack the early days, it would be good to see more of the origins and things that made Slack, Slack.

The posts have some of the founding documents too...

"Be harsh, in the interest of being excellent."

We don't sell saddles.