W3Perl - Screenshot

Summary

Informations are available for domain stats, external stats and both.

The number of requests (hits) is the number of files accessed. It includes images, HTML pages, scripts or any others kind of files.
The number of HTML pages read (accesses) is a more accurate unit as only HTML page are counted. But with framed website, you can easily increase this number.
Trafic is the number of bytes people have downloaded. It give an idea about the bandwidth you need.
Number of differents HTML pages read : if all your website have been read, this is the total number of HTML files in.
Number of differents hosts : this is not the number of visits as one host is not one person. Many people can use the same hosts and many hosts can share the same person....but this is a first guess.
Number of differents countries : people around the world

This is the number of requests which have been excluded from your configuration file.

from a proxy (Proxies can make a request to your server asking if the request file have been expired or not, depending of the proxy configuration, thus file are downloaded from a cached host, not from the server)
Redirection (the file has moved to another place)
Unathorized access (you are not allowed to access the file)
Forbidden access (you can't access the file)
Not found file (this file doesn't exist)
Pages excluded by your configuration file (file you have asked to ignore)
Hosts excluded by your configuration file (hosts you have asked to ignore)
Spammer excluding (you choose to exclude the spammer referer host)
Frames excluding (you choose to exclude the main framed pages)
Robots excluding (you choose to exclude robots requests)