Slack collects and retains employee data

Examples
Date

Despite being a subscription service that doesn't depend on advertising revenue, Slack (owned by Salesforce) collects a large amount of data on the people who use its system, including details provided voluntarily at sign-up, when and how people use the platform, and information about third-party services users connect to it - and never deletes any of it. Users newly added to a channel can read the entire range of historical messages and files. Messages users send are controlled by the workspace owner, which in most cases is their employer, and that person or organisation decides how long messages are kept and what data to extract. With Slack's cooperation, employers can even gain access to workers' private messages. 

https://www.wired.co.uk/article/slack-privacy-settings-notifications

Publication: Wired

Publication date: 2020-10-27

Writer: Matt Burgess