By holding the cursor over an option, you will get an explanation of the usage.
Clicking on a hostname in the output will add it to the hostnames list. Clicking on a nameserver will add it to the "Specify" list.
Fair usage policy:
This tool is not intended for automated lookups. Any other usage is in general welcome and free. To prevent abuse a reCAPTCHA needs to be solved for every 100 lookups in a 24 hours period.
This online GUI interface to dig was created by Yajun. I welcome your comments and suggestions!