Hmmm… A search using NN and Unknown in the first name field quickly reveals the magnitude of the problem. Both produce 5000+ people. As someone mentioned, it’s impossible to search on --- or ???.
Ideally (wearing a few hats from my various roles in my working life), whoever runs Geni would set up a project team to explore the issue and come up with a “best solution”, the team consisting of a users’ group (consisting of experienced and amateur /newbie genealogists and a librarian or two), a project manager, and IT business analysts. Once a best practice or standard is decided, it wouldn’t be too hard to translate business rules into IT programming logic, to steer users in the right direction, e.g. say “NN” is decided and the user starts entering “Unknown” or “???” (or anything from a long list of variants added to this list of likely but unacceptable entries).
However [sigh], coming back to the real world… just a glance over this thread is enough to reveal that there’s never going to be consensus, leave alone a standard set by users alone…
I personally think that a lot more could be done in the very early stages to prevent people going beyond a certain stage without reading some essential guides, which could be done as a kind of simple tutorial with a series of pages that need to be navigated through and ticked off before being let loose to play havoc with the existing database. (This thought occurred to me after learning more about the endless problems with duplicates and merges – and having made a few basic errors myself along the way when I was setting up my first few profiles.)
But, getting back to the issue under discussion, it looks as if for the foreseeable future, people are just going to carry on doing their own thing and sticking to their own preferences. I can see justification for everybody’s opinions here (and some great questions have been raised), but unfortunately it looks as if there’s no way to enforce a standard.
My own opinion? I am now back to leaning towards Unknown, or perhaps even in parentheses, i.e. “(Unknown)”, which would make it clear to others reading it in different languages. If I saw (Inconnu) or (Okänd) or (Ajnata), I would conclude that it wasn’t a name.
NN is good in theory, and if it were just genealogists and OCD people like me who are likely to look for rules about these things, or everyone was familiar with Latin abbreviations, but let’s face it, everyone and their dogs are recording family trees online these days, and not everyone is as pernickety about getting things right, or what the database looks like. Also, some people use full stops with it and some don’t, compounding the variations.
--- and ??? both have merit, imo, but also drawbacks as mentioned by others.
Thanks to everyone for the thoughtful responses and discussion though – hopefully at least partially fruitful and useful to some people.