Your Slack Channels Are a Courtroom. Does Your Legal Team Know That?

The message was sent in a private Slack channel between two product managers. It was casual, direct, and four words long. At the time it was typed, no one imagined it would appear in a federal courtroom. But when litigation began, opposing counsel requested Slack communications — and the court compelled production. The four-word message became the most-quoted line in the deposition.

This scenario is no longer unusual. According to Gartner research on workplace collaboration, the majority of knowledge workers now spend more time in chat platforms than in email. The decisions, approvals, complaints, and strategic discussions that once lived in inboxes now live in Slack channels and Microsoft Teams threads. Courts have made clear — through compelled production orders, sanctions for non-preservation, and explicit rulings — that collaboration data is fully subject to Rule 34 discovery requests. It is ESI. It is discoverable. And most organizations are not collecting it correctly.

The judicial record on collaboration platform ESI is now well-established and unambiguous. In Lubrizol Corp. v. IBM Corp., a federal court ordered IBM to produce targeted sets of Slack and Microsoft Teams messages. In RIG Consulting v. Rogers, a court compelled production of Teams account messages and emails within 28 days and awarded fees against the resisting party. The DOJ and FTC reinforced preservation duties for Slack, Signal, and chat platforms in explicit agency guidance following spoliation rulings.

Perhaps the most instructive case is Charter Communications Operating v. Optymyze, where the company attempted to produce Microsoft Teams chats as 87,000 one-line emails. The Delaware Court of Chancery rejected the production entirely and ordered native chat production. The message was clear: chat data must be produced in a format that preserves the conversational context that makes it meaningful evidence.

The challenge for legal teams is not that collaboration data is discoverable — that has been settled. The challenge is that collecting it correctly requires a fundamentally different approach than email collection, and most organizations have not built that approach into their standard workflows.

Defensible collection of collaboration platform data requires attention to several elements that simply do not exist in email collection. Threading must be preserved — a Slack reply that appears three days after the original message must be collected with the full thread context, not as a standalone entry. Edited messages must be captured, including the original content and the edit history. Deleted messages, where they exist in the platform's retention system, must be preserved before they age out. Reactions, file attachments, and app integrations may all be relevant evidence depending on the matter.

For Microsoft Teams specifically, the fragmented storage architecture creates collection complexity that requires Microsoft Purview eDiscovery Premium — not standard eDiscovery features — to handle correctly. Chat messages in Exchange Online, files in SharePoint, personal files in OneDrive, and meeting recordings in Stream must all be addressed. Cross-tenant collaboration data — messages between your employees and external vendors in shared channels — requires coordination with the external organization's IT team, because the data hosted on the other tenant cannot be collected through your own Purview instance.

Documentation of collection methodology is critical for defensibility. Record the export method used, the date and time of export, the scope parameters applied, any filters, and the identity of the person who performed the export. If opposing counsel challenges completeness, that documentation is what allows you to demonstrate that you used a reliable method and captured everything within the defined scope.