The "Usage Log" and "Error Log" links (see above picture) will take you to text version of each log file. The usage log provides the IP address of the requester, time and date of the request, and the description of the request. The "Stats" link (see Subdomain Statistics section) is a graphical version of the usage log. The error log provides information about unsuccessful requests and is useful for troubleshooting when the cause of the error is unknown.
The usage and error logs are accessible immediately after subdomain creation. You will see a blank box if there has been no subdomain activity.