Username mention
Also called: u/ mention, tag someone on reddit, user mention, summon
Definition
A username mention is typing u/ followed by a Reddit username in a post or comment. It links to that user's profile and normally notifies them, so it works like tagging. Mass-tagging people who did not ask is treated as spam.
A username mention is Reddit's version of tagging. Write u/username in a comment or post and Reddit turns it into a link to that person's profile and, unless they have turned it off, sends them a notification. The same pattern works for communities: writing r/name creates a link to a subreddit, which Reddit calls a community mention.
How it works
- Format: u/ plus the exact username, for example u/spez. The older /u/username format works as well.
- Notification: the mentioned user gets an inbox notification, depending on their notification settings. Reddit lets users toggle notification types on or off in Settings, then Notifications (or Manage notifications in the apps), and says most notifications expire after 7 days.
- Reliability: mentions have had edge-case bugs; Reddit's April 2026 changelog, for instance, records a fix for mentions of usernames ending in a hyphen.
Mentions are common for crediting someone ("u/name explained this better in another thread"), pulling in the OP of a related post, or calling a bot that responds to being summoned.
Why it matters for marketers
Mentions are useful in two directions.
Inbound. If people mention your brand account by username, you get notified, which makes your brand account easy to reach. Keep notifications on for a brand account so you actually see them. Mentions of your brand by name (without u/) do not notify you; those need search or brand mention monitoring.
Outbound, carefully. Mentioning someone pulls them into a thread they may not have chosen to join. Reddit's spam policy lists "mass-tagging other users" next to unsolicited mass messaging as a violation. Tagging a dozen people under your launch post, or tagging a competitor's customers, is the fast route to reports and removals.
Reasonable uses for a business account:
- Crediting a user whose feedback led to a feature.
- Replying across threads to someone who asked you a question elsewhere.
- Pulling in a teammate (clearly labeled) who can answer a technical question.
Example
A user posts "has anyone from [Company] seen this bug?" without tagging anyone. The company's support account never gets notified and does not see it for a week. A month later, another user writes "u/CompanySupport is this fixed?" and the account replies within an hour. Same question, different visibility, because of the mention.
Frequently asked questions
How do I tag someone on Reddit?
Type u/ followed by their exact username in a post or comment. It becomes a link to their profile and normally notifies them.
Does Reddit notify me when someone mentions me?
Yes, by default, unless you turned that notification type off in your notification settings.
Is it spam to mention users on Reddit?
Mentioning one person for a relevant reason is normal. Tagging many users to get attention is mass-tagging, which Reddit's spam policy prohibits.