There is no special meaning for the plus sign in the user names report. It seems that either some user names are logged with this sign for some reason, or that there is a problem with your log format so the program incorrectly appends the plus sign to some user names.
If you send a sample log file from your site to us at support@weblogexpert.com we'll check if there is a problem with the log format in this case.
If you send a sample log file from your site to us at support@weblogexpert.com we'll check if there is a problem with the log format in this case.