Data sold or shared with third parties
“Slack does not sell (as such term is defined in the CCPA or otherwise) the personal information we collect (and will not sell it without providing a right to opt out). We may also share personal information (in the form of identifiers and internet activity information) with third party advertisers for purposes of targeting advertisements on non-Slack websites, applications, and services.”
What that means: Your browsing and activity data, specifically identifiers, can be shared with third-party advertisers to target you with ads outside of Slack's own services.
While Slack explicitly states it does not 'sell' personal information, it does admit to sharing 'identifiers and internet activity information' with third-party advertisers for targeted advertisements on other platforms. This practice of sharing data for advertising purposes can be considered a form of 'sale' under broader privacy definitions or implicit data monetization.