I haven’t seen the other topic yet, but I think nationality is next to useless. Much more useful would be spoken languages. People speak multiple languages (at least in most of Europe), so it if anything, then this should be based on languages spoken, not nationality. That way, if multiple languages are spoken, the user could indicate one primary language, and others can still contact the person if they don’t speak the primary language, but do speak one of the secondary languages.
However, it was not about nationalities, but more about languages. The point was, that if everybody could choose little icons for the languages he speaks, it would be easier for you to know in which language you might want to contact him, concerning an IL for example! Usually english works fine, but if you are not a native speaker, than it would be much more comfortable to wright in your own native language. Just search the forum, and you will find the topics both on the german and english board. Back then, many here agreed with this suggestion. Anyhow, i don´t know yet if it made it on the official to-do list