The Auth User is simply the string typed into the name field of the authorization dialog. This name is not present for pages which are freely accessible and does not nessesairly have anything to do with the actual name of the person making the request. NCSA Common and Combined logs both have the Auth User name. WebSTAR logs this name when the USER token is in the log format. BPS - Bits per second.
Summary decodes the standard methods of partially hiding the identity of the browser in most cases.
CGI Arguments - A URL can optional contain a question mark, the portion of the URL to the right of the question mark is often referrer to as the search argument or more generally as the CGI argument. This portion is traditionally passed to a CGI program for interpretation. Many end users disable this feature of their web browsers however. The length of the current time period is configurable, generally one week. On the internet most computers are given names which can be used to access them over the internet.