wp-visitors keeps track of information about every visitor (page load).
Yes. If you know basic HTML and some PHP, you should be able to change it.
It links to the ARIN WHOIS database and provides some more information that you may (not) find useful.
Very valid question. Like #3, this feature will be added in a subsequent update.
Another valid question. This feature will be included in a subsequent update.
Good idea (thanks to Kyle Schneider and Amy Krause)! This will also be included in a later update.
Another good idea (thanks to Richard Tape). This is also being worked on and will be included in a later update.
Over 95% of it is accounted by the data that maps an IP address to geographical location.
Excellent question - in its earlier versions, this plugin was causing some unforeseen errors effectively disabling the login screen and adding lot more complexity to your already complex life. This update fixes that issue. No more such errors - thanks to Amy Krause for testing it out!