What should we do about duplicate, unregistered user accounts?

Question

We have at least a couple users who post regularly and never register accounts. Each time the cookies on their computer get cleared, they lose their old unregistered account and are given a new one. If we know of users like this, do we need to do anything about it?

• Possibly the best well-known example is M.A. Golding. He had a dozen or so accounts until recently. Now he's down to three accounts because of a meta post on movies.SE.
• Another example is PMar, who currently has 16 accounts, assuming that all of those are the same person.
• Random Passerby has 16 accounts, unless we have multiple random passersby.
• Are all 13 of The Doctors the same person? What about the 11 revenants? Who knows!

Is this a problem? CMs can merge accounts, but I thought until recently that they only did that at the request of the owner of the accounts.

Answer 1

Other than leaving a comment resembling something like:

Are you [this user with a similar name]? If so, you might want to merge your accounts, otherwise you'll lose the reputation and privileges gained by the other account

There's nothing we ("we" being everybody who isn't an SE employee) can or, indeed, should do.

Users have the right to choose how they interact with the site

Within some reasonable limits, of course; but although registration is strongly encouraged, it's not required. It's entirely possible that a user may not know about the difference between a registered and an unregistered account, in which case pointing them to the "merge my accounts" FAQ page will sort them. But maybe a user does know, and are intentionally choosing to use an unregistered account. That's their decision, and it's not against any rule (or any sensible proposed rule).

Is it even really a problem?

What are the actual consequences of this scenario?

• Unregistered users can't vote on posts, so bad sockpuppetry is basically impossible
• There's no reputation restriction on asking or answering, so we're not deprived of quality content

As far as I can tell, there are only a few actual negative effects to the community, all of which are negligible at best:

• We lose a chat contributor. Chat is a third-class citizen anyway, and I'm not comfortable basing site policy around it, but we're also not exactly hurting for chatters
• We may lose quality comments. Comments are second-class citizens anyway, and mods can convert answers to comments if they feel it's necessary. I'm not bothered
• We lose someone looking over the queues. To take an easy example, the M.A. Golding users have enough combined reputation to handle all of the queues, assuming they're all the same person (a questionable assumption in itself). But considering the normal state of our queues, I think we can handle it

• A user might use unregistered accounts to circumvent a ban. This is the one thing I agree is a potential problem. If the user is posting garbage, then we already have systems in place to deal with that; the VLQ queue, spam flags, and account deletion.

  Otherwise, there's too much ambiguity for anybody not on the SE payroll to assume liability for getting it wrong. How do we know an unregistered account belongs to a banned user?

  • Username? Seems way too likely to generate false positives
  • Email address? Only if they're really dumb
  • IP address? What about shared computers?

  There's a cost-benefit analysis to be done here, but this one may be something that SE monitors internally, if they're not already. But handling this use case is above our pay grade

Answer 2

If you suspect two unregistered users are the same person ...

The best (and often, the only) thing to do is to leave a comment as Jason suggested:

Are you [this other user]? If so, you might like to merge your accounts so that you keep all your posts under one account and have privileges such as being able to edit your posts by yourself.

In really clear-cut cases (e.g. one user asks a story-ID question, another user with the same username suggests an edit to add more details; or two users make two word-for-word identical posts), you could flag one of the relevant posts for moderator attention. We have more tools to investigate such issues, and also easier access to those with the power to actually merge accounts.

However, in most cases it's not something you need to worry about too much; the only person who loses out from the two accounts not being merged is the person who created them. Having more than one account is allowed, provided you're not doing anything nefarious with them, so you don't need to flag for moderators every time you come across a user with two accounts. In particular, if the person is deliberately maintaining two accounts and is open about it (e.g. Buffybot or Awesome Frog), then chances are there's nothing bad going on and nothing you should do about it. However:

If you suspect foul play ...

Although you don't have to raise a flag every time you come across two accounts that seem to be the same person, please do let the mods know if you've found some real nefarious activity. This is part of what the flagging system is for: you help us to police the site, and flags are how you let us know about things that might require our attention. Just bear in mind that you may not receive any feedback on your flag, as these things often need to be dealt with privately.

(I realise this isn't what you're really asking about: you're focusing on unregistered users who accidentally create more than one account, rather than sockpuppeteers. But I wanted to make clear that there are situations when it's good to flag even if the case isn't clear-cut from the non-mod perspective; and since others here have raised the issue of new accounts being created to circumvent a ban, I thought I'd mention this possibility too, even if only briefly.)