Since Piwik 1.9 it´s possible to determine location of visitor IP’s with Maxmind´s GeoIP Databases.  More

If you are using nginx, follow this tutorials:
– Using GeoIP With Nginx On Debian Squeeze/Ubuntu 11.04
– How do I install the GeoIP module for Nginx? (Piwik FAQ #166)

See result: http://seo-quick.info

GeoIP Databases cron update:

#!/bin/bash
cd /etc/nginx/geoip
wget http://geolite.maxmind.com/download/geoip/database/GeoLiteCountry/GeoIP.dat.gz
gunzip -f GeoIP.dat.gz
wget http://geolite.maxmind.com/download/geoip/database/GeoLiteCity.dat.gz
gunzip -f GeoLiteCity.dat.gz