Hmmm... just found this while looking through the ixtab.tk logs:
72.21.217.98 - - [06/Mar/2013:16:01:43 -0600] "GET /robots.txt HTTP/1.1" 200 52 "-" "Mozilla/5.0 (compatible; AMZNKAssocBot/4.0 +http://affiliate-program.amazon.com)"
Now...
Should I be proud, amused, or worried?