The methods that are used to collect the data aren't described fully.  The wiki article does specify that "It is currently still unknown how reliable this information is."
  - http://en.bitcoin.it/wiki/Bitcoin_Map

There have been some developments including "split channel" for the IRC and DNSSeed, so it is possible the data collection method initially used is incompatible with the changes.


Google maps won't render the live data ( https://smsz.net/btcStats/bitcoin.kml ) , presumably because the KML data has grown too large:
  - http://maps.google.com/maps?q=https://smsz.net/btcStats/bitcoin.kml

So that we have at least a relatively current working view of the map, I published a link with a snapshot from July 6th after ripping out all data except for ip address and location.
  - http://maps.google.com/maps?q=http://c1958612.r12.cf0.rackcdn.com/bitcoin.kml