# Reactions & Comments
URL: https://usememos.com/docs/usage/reactions-comments

Beyond writing your own notes, Memos supports lightweight collaboration on memos: emoji reactions, threaded comments, and user mentions. These work on any memo you can see, subject to visibility and sign-in.

## Reactions [#reactions]

React to a memo with an emoji from the reaction selector in the memo header.

* reactions are available to signed-in users on any non-archived memo, including memos in the Explore feed
* click an emoji to add your reaction; click it again to remove it
* the set of allowed reactions is configured by admins in **Settings → Memo**

Reactions are a fast way to acknowledge a memo without writing a comment.

## Comments [#comments]

Open a memo's detail page to read and add comments.

* the **write a comment** button appears when you are signed in
* comments support the full Markdown editor, just like memos
* each comment is stored as its own memo nested under the parent, so it can be reacted to and linked directly
* the memo's author is notified in their [inbox](/docs/usage/inbox) when a new comment is posted

Comments live on the memo's detail page rather than in the main timeline, which keeps feeds focused on top-level notes.

## Mentions [#mentions]

Reference another user inside a memo or comment with `@`, for example `@alice`. Mentioned users receive a notification in their [inbox](/docs/usage/inbox) linking back to the memo, which makes mentions useful for looping someone into a note or comment thread.

## Good habits [#good-habits]

* use reactions for quick acknowledgement and comments for anything that needs a reply
* keep comment threads on-topic with the parent memo
* mention people sparingly so notifications stay meaningful
* remember that anonymous viewers of a public or shared memo can read reactions and comments but cannot add their own