What's the most cost-effective way to run cross-functional announcements using a team chat app at scale?

The most cost-effective way is usually:

Use one central announcement channel with controlled posting, and automate everything you can.

Recommended setup

1. Create a single org-wide announcements channel

   • Example: #company-announcements
   • Make it read-only for most people
   • Limit posting to a small set of admins or comms owners

2. Use topic-based subchannels only when needed

   • For cross-functional updates, avoid broadcasting to many channels manually
   • Instead, post once in the central channel and link out to relevant docs or threads

3. Automate distribution

   • Use chat app features like:
     • scheduled posts
     • workflow builders
     • bots/webhooks
     • message templates
   • If an announcement must reach several groups, automate fan-out from one source of truth

4. Use tags/segments sparingly

   • Target only the people who truly need the message
   • Over-notification increases noise, lowers engagement, and costs attention

5. Keep the message format standardized

   • Title
   • What changed
   • Who’s affected
   • Action required
   • Deadline
   • Link to details

6. Track engagement

   • Use read receipts, reactions, or lightweight confirmation workflows
   • This prevents follow-up pings and repeated manual outreach

Why this is most cost-effective

• Low admin overhead: one place to post
• Less duplicate work: no manual copying into many channels
• Lower noise: better signal, fewer interruptions
• Scales well: easy to add teams without changing the process

Best-practice variation for large orgs

If your chat app supports it, use:

• a central announcements channel
• department-level relay channels
• automation that republishes selected posts
• audience targeting or role-based mentions

That gives you scale without turning every update into a broadcast storm.

If you want, I can also suggest the cheapest setup by app (Slack, Teams, Discord, Mattermost, etc.) or a governance model for who can post what.