Activity Log file

umm. theres sort of if you count the Raw Log files the server produces, which could be tracked by IP address.

You could also look at Google Analytics, and you could add the username to the google stats

There isn't as this would mean setting insure permissions on the server and effect performance, especially on busy forums where everytime a user clicked a page you would need to load in a log file add another line to it and then save it back to the server.

Is there really much point as all you are doing is duplicating the data in the IIS site logs.

The will do if setup correctly as they give the page URL the user is looking at, for example in the log files you would have:-

2007-12-20 00:03:35 GET /forum_posts.asp TID=25039&PID=129615 - 65.55.208.169 HTTP/1.0 msnbot/1.0+(+http://search.msn.com/msnbot.htm) - 200 0 49472

This shows what page the MSN bot locked at and the which post, if you follow the link you would go directly to the topic.

If the log files are a bit to RAW for you then there are loads of log file annalist programs that you can get. We use SmarterStats Enterprise which has over 140 different reports with loads of information including browsers, were they come from, etc.