Add Slack broadcast learnings to handbook

[charlescook-ph]

Changes

Adds practical learnings from running a Pylon Slack broadcast to all managed customer channels, to the Slack messaging handbook page:

• Checking with Sales – ping more than once and give a final heads-up with the scheduled send time so people get a last chance to flag exclusions.
• New "Excluding channels before you send" section – drop legacy/archived channels, scan #posthog-* channels for recent negative sentiment (an LLM can do this sweep), and consider excluding (or wording around) accounts that already use the feature.
• Sending in Pylon – send as yourself, not as PostHog.
• Tone – a light, self-aware "this is an automated message" tone lands well and pre-empts spam complaints.
• Cadence – rough guide of no more than one broadcast every couple of weeks.
• New "After you send" section – replies land in your private Slackbot thread (not shareable; replies outside the thread are invisible unless you're in the channel), and judgement on answering yourself vs. routing account-specific questions to the TAM/CSM.

Checklist

• I've read the docs and/or content style guides.
• Words are spelled using American English
• Use relative URLs for internal links
• I've checked the pages added or changed in the Vercel preview build
• If I moved a page, I added a redirect in vercel.json (n/a – no pages moved)

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Created with PostHog Code

[github-actions]

Deploy preview

Status	Details	Updated (UTC)
🟢 Ready	View preview	Jun 06, 2026 10:18AM

[github-actions]

Vale prose linter → found 2 errors, 8 warnings, 0 suggestions in your markdown

Full report → Copy the linter results into an LLM to batch-fix issues.

Linter being weird? Update the rules!

contents/handbook/marketing/slack-messaging.md — 2 errors, 8 warnings, 0 suggestions

Line	Severity	Message	Rule
9:112	warning	'comms' is a possible misspelling.	PostHogBase.Spelling
19:29	warning	'comms' is a possible misspelling.	PostHogBase.Spelling
24:4	warning	'Check with Sales before sending' heading should be in sentence case, and product names should be capitalized.	PostHogBase.SentenceCase
31:67	error	Hi, Andy here... use an en dash ( – ) with spaces. On Mac, holding down the Option and hyphen key will give you an en dash.	PostHogBase.EnDash
33:37	warning	'PMMs' is a possible misspelling.	PostHogBase.Spelling
43:4	warning	'How to send a broadcast in Pylon' heading should be in sentence case, and product names should be capitalized.	PostHogBase.SentenceCase
49:85	error	Hi, Andy here... use an en dash ( – ) with spaces. On Mac, holding down the Option and hyphen key will give you an en dash.	PostHogBase.EnDash
57:29	warning	'comms' is a possible misspelling.	PostHogBase.Spelling
64:46	warning	'Slackbot' is a possible misspelling.	PostHogBase.Spelling
65:38	warning	Use American English. Use 'judgment' instead of 'judgement'.	PostHogBase.AmericanEnglish