Tim, I am reluctant to divide the site up into country-specific sections.
The benefits that brings – (immediately easy to see who is recently online near you, personal ads only relating to your country etc.) – would be far outweighed by the downside: everyone compartmentalized, nobody reads anything by anyone outside their area etc. Suddenly the site would look very empty, unused, dull. Especially for those outside the USA.
At the moment, with everyone lumped in together, it looks busy. It encourages interaction.
That’s my opinion, at least.