On a Social Networking site, is it generally a good idea to allow the reuse of old usernames from deleted accounts, or is it better to prohibit their reuse forever?

How do the big boys do it (Facebook, Google, etc.)?

Generally, as far as the DB is concerned, it's not a big deal either way because most tables are associated by some kind of user id, and not the username.

I can certainly see why you wouldn't want to allow the reuse of BANNED usernames, but what about usernames from accounts that were simply deleted by the original owner? Do you free up those usernames or do you prohibit their reuse?

Pros of allowing reuse:

  • Frees up available username space.
  • Current account owners can "reset" their accounts by simply deleting it and quickly re-registering it with the exact same username.

Cons of allowing reuse:

  • Can create confusion. Imagine an old user with thousands of posts on a forum. They delete their account, their posts remain under the old username, and someone comes along and registers with that same username. It will seem like that new user created all those old posts. Sure, you can change the username of the old user prior to deleting their account to avoid this confusion, but wherever they've been quoted, you will still have their original username, which can still create confusion.
  • Can be "gamed". Imagine a very popular user deletes their account and someone quickly re-registers that username in order to benefit from the "trust" associated with that username, and possibly uses it maliciously against unsuspecting users.

Any other pros/cons I'm not thinking about it? I'm really curious to learn how the big boys do it and why.

4 Answers 4


Basically you're already answering your question yourself. One thing to add: If you prohibit the re-use of outdated user names, you always can offer former users to come back and re-use their account under their old user name. Btw. this is how Facebook does it. And if you believe (I do) that many companies don't really ever want to delete information they once have, you can imagine that most sites don't delete old data but simply deactivate it. In order to not break the database indices, also the deactivated user names will stay "unique" and can't be taken over by someone else. The points you mentioned speak for this practice, too. The fact that users are identified by ID rather than by user name could imply that anyone can take the same username at the same time, but this would then not be any concern to your question.


I would say that it's fine. On most forums you will likely on have a handful of long term and well known users, so you if they decided to delete their account, you could add their usernames to the banned usernames list. (This would probably be done manually but you could base it on number of posts/reputation they had.)

If any posts from the previous user remain on the site then you should rename said previous user (eg to 'user1234') to avoid any confusion. This is a good idea anyway when someone deletes their account, as their username could contain personal information.


As I know, some sites use both way together. for example, when you delete your Yahoo! account, they allow you to reactive your account in certain period of time(90 days for Yahoo!). If you haven't done it , So Yahoo! will delete your information and allows others to reuse your id.


Re-use is terrible bad idea, due to 1 Contra reason

Prohibit impersonation in any from and protect IP of old users all time - Internet does not end today, and just outside your site... and user's text and usernames are linked

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