Slack now has deeper integration with Office apps and files including full previews of Office files like PowerPoint slides and new Outlook and OneDrive apps
Available to Slack users today — Slack is integrating Microsoft's Office 365 services today.
Context & Ripple Effects
When Microsoft launched Teams as an Office 365-bundled Slack rival in 2016 and then switched it on by default for every Office 365 business tenant, the bet was that native Office access alone would make Slack dispensable. Today's integration is Slack's countermove: rather than fighting the bundle, it plugs into it, adding full previews of PowerPoint slides and dedicated Outlook and OneDrive apps.
First-order effects
- Office-centric teams weighing Slack against Teams lose their main reason to default to Microsoft's bundle, since decks, documents, mail, and cloud files now live natively inside Slack channels.
- For Microsoft, the deal hands Slack the same Office stickiness that anchored Teams' pitch, weakening the exclusivity that made the bundle compelling.
Second-order effects
- The move pressures Microsoft to differentiate Teams through capabilities Slack cannot simply integrate away, because shared Office access is no longer a moat.
- Rival enterprise vendors take the same lesson: interoperability with incumbent file formats is table stakes, shifting competition from lock-in to integration depth.
Third-order effects
- If the pattern holds, chat platforms converge into neutral work layers sitting above office suites — a trajectory Slack itself confirmed by later adding Teams calling integration and borrowing Teams' layout in its biggest redesign.
- Workplace software competition migrates from owning documents to routing work across them, favoring whichever platform mediates the most daily workflows regardless of who authored the files.
The trend: Chat platforms are evolving from message boards into neutral work surfaces layered across rival office suites, competing on workflow rather than file ownership.