One of the obvious things you’ll need are flag graphics for the nationalities. Have you found these yet?
Yes, check out this page:
https://github.com/NoahY/q2a-flags
It’s a script that’s suppose to do what I suggest (and they even have all the flag graphics in different sizes in the link) but I couldn’t activate the plugin on my site – I think you need to have this Questions2Answers thing installed…
+1
Other than “Nationality”, I would also add “Resides In”.
There’s at least 2 plugins for wordpress that handle flags according visitors IP to do some function. I guess one of them makes use of shortcodes to put anywhere (posts, pages, widgets) to display some visitors country flag.
Ipgp User Country Flag
The plugin will show your visitors their country flag, based on their IP Address. You can add it as a widget to your sidebar, using a shortcode in your post or pages or directly in your template trough template tags.
Maybe you can go with this one, If you do I’ll be glad to know how did you solve it.
There’s another plugin I’ve just found:
Quick Flag
try the QUICK FLAG plugin (http://www.techytalk.info/wordpress-plugins/quick-flag/), it will get you half way there