This page shows the last 300 error messages in reverse order with the time, IP address of the visitor and the URL that caused the error.
It can be useful for de-bugging scripts you are testing, seeing if you have any missing files or broken links and for seeing if people are trying to cause mischief on your account!
Popular entries in the error log:
Example of robots.txt entires
That lists the folders not to be searched. For more information on robots.txt do a search on robots.txt on Google