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Open Thread 421

2026-02-16 · 09:14 UTC ·Astral Codex Ten ·2 min read

Brief

Open Thread 421 is a short Astral Codex Ten housekeeping post opening the weekly public discussion thread for reader comments. Beyond pointing readers to related community venues such as Reddit, Discord, a bulletin board, and meetups, it contains no argument, research, metrics, or technical content; most of the email is platform UI and subscription/upgrade links.

Why it matters

Astral Codex Ten’s Feb. 16, 2026 post is a routine community open thread rather than a substantive essay or reported article.

Key details

  • The post is titled “Open Thread 421,” published on Substack by Scott Alexander on 2026-02-16, and consists mainly of an invitation for readers to “post about anything,” ask questions, and use the comments as a general discussion forum.
  • It links to ACX community spaces including an unofficial subreddit, Discord, bulletin board, and in-person meetups, but provides no original analysis, data, technical claims, or domain-specific reporting.
  • The remainder of the email is primarily subscription prompts, sharing buttons, and standard Substack footer material.
Cleaned source text

title: Open Thread 421

author: Astral Codex Ten

content_type: newsletter

publication: substack.com

published: 2026-02-16T09:14:39+00:00

source_url: gmail://19c65bb565e76255

word_count: 347

͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­͏ ­

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Open Thread 421

Feb 16

READ IN APP

This is the weekly visible open thread. Post about anything you want, ask random questions, whatever. ACX has an unofficial subreddit, Discord, and bulletin board, and in-person meetups around the world. Most content is free, some is subscriber only; you can subscribe here.

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© 2026 Scott Alexander

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