Use two fields: name and display name. Anything else will break for someone. In most cases where something asks for my name its really not even necessary and certainly not necessary to split it into first/last/display/friendly etc.

This is not sufficient if you’re going to localize to languages other than English. In some languages, proper names get declined like other nouns and thus change spelling in different contexts.

Are there examples where splitting it in First/Last name (or any other split) would help with that? It seems like that would always either be a problem or something to design around while localizing.

It’s fundamentally language specific, so any comprehensive solution is going to need to interface with the localization system. Really, names should be keyed by (user, language, tag) triples, where the localization defines the acceptable tags based on language requirements. For example, a single person may need their name stored as:

  en:disp     Eric
  is:disp:nf  Eiríkur
  is:disp:þf  Eirík
  is:disp:þgf Eiríki
  is:disp:ef  Eiríks

Designing a UI to collect this information is left as an exercise for the reader.

Since asking a user to enter every possible variant is unwieldy and without doing so, the problem is unsolvable, I’ll stick with my original suggestion of using a single field. Yes, some names will break, but far fewer than if first and last names are required.

A lot of software would be much better without stupid clients asking for the wrong things.

Eh, I understand it. They want to put some name in the identity control in the header. Putting the full name in is guaranteed to go wrong. We might start asking for a nickname for that purpose.

Why is the full name guaranteed to go wrong? A better assumption is that there is no reasonable nickname and you have to use their full name.

You're assuming that you're 'friendly' enough with your users that they want you to use their given name.

Oh yeah that touches a nerve. I hate it when I have filled in my name and email somewhere, maybe I forgot doing it, and I receive a newsletter, which opens with and greets me with just my first name.

No. Just because I signed up for your mailinglist doesn't mean we're on a first name basis! I hardly even remember your business exists, do you remember me? Anything else about me except my email and my full name, from which you deduced my first name? Then let's not pretend we're buddies.

This of course depends on how "friendly" I'm willing to be with said business. Which differs if it's an Etsy store, ordering food online, my bank, insurance, etc. I especially hate it when the news letter is in fact 99% ads and promo babble, but has this 1% of useful info that I want to be kept up to date on. We're not close, I'm letting you spam my inbox, call me "your grace" or something.

Can you actually go wrong with just using someone's full name, and erring on the side of being a tad too formal? Is this just a problem with marketing companies that want to "connect" and become "buddies"?