Slack vs Signal

Slack collects account details, logs, device information, approximate location, cookies, imported contacts, third-party integration data, and audio/video metadata. That gives Slack a fairly detailed picture of how you and your device use the service.

Owners and administrators may be able to access, modify, or restrict access to information, including profile details and workspace activity logs. In a workplace account, your employer may therefore have substantial visibility into your use of Slack.

If a workspace enables third-party services, Slack may receive and share information with those providers, and those services run under their own policies. Users should assume integrated apps can expand where their data goes.

Slack keeps non-customer personal data as long as necessary for support, legal compliance, disputes, and business purposes, including after account deactivation. That means some data can persist well after you stop using the service.

Slack transfers personal data outside your country, including to the United States and other countries. While it cites safeguards like Standard Contractual Clauses, cross-border transfers still increase jurisdictional exposure.

Slack says users may request access, correction, and deletion of personal information, and can use account settings tools where available. For workspace-controlled data, though, you may need to contact the customer/administrator.

California users get CCPA/CPRA rights, including deletion, disclosure, and opting out of certain ad-related sharing. Slack also recognizes Global Privacy Control for cookie-based sharing signals.

Slack uses personal data to send marketing emails and other promotional communications. You can control some of these messages, but marketing is still an express use of the service data.

If you use Slack through an employer or other customer, that organization controls workspace settings and Customer Data. Practically, this means your message and file access rights may depend more on your workspace admin than on Slack itself.

The terms expressly say the Slack Terms are a binding agreement. This is standard, but it means use of the service is legally governed by incorporated agreements you should read carefully.

Signal explicitly says it does not sell, rent, or monetize your personal data or content. That is a strong privacy commitment compared with many ad-supported services.

Signal says it cannot access the contents of your messages or calls because they are end-to-end encrypted. In practice, this sharply limits what the company can read or disclose about your communications.

If Signal harms you, its total contractual liability is capped at $100 to the extent allowed by law, and many categories of damages are excluded. This significantly limits practical remedies.

The policy says message history stays on your devices and that server-side technical data is limited to what is necessary to operate the service. This reduces the amount of personal information retained centrally.

You must sign up with a phone number and accept verification texts or calls. That creates an identity link many privacy-conscious users may prefer to avoid.

Disputes must be brought in specified California courts under California law. This can make it harder or costlier for non-California or international users to pursue claims.

Signal can update its terms and privacy policy, with continued use treated as acceptance, and it may suspend or terminate access at any time for any reason. Users have limited leverage if terms worsen or access is cut off.

Signal states that you own the information you submit through the service. Notably, the terms do not describe a broad content license letting Signal exploit user content.

If you use contact discovery, Signal may hash address-book data and send it to its servers to find other users. This is optional and privacy-protective by design, but still involves sharing derived contact data.

Signal says encrypted information and metadata may be transferred to the United States and other countries where it or its providers operate. Users outside those countries may face different legal protections.

Signal is not a substitute for emergency services. Relying on it in a crisis could be dangerous because it does not connect to police, fire, hospitals, or similar services.

Users can manage personal information and enable extra protections like a Registration Lock PIN in the app settings. This is a useful transparency and account-security feature.