I just checked a log file from my mail server and noticed quite a bunch of deliveries. Turned out one address on my domain was being spammed with over 13 thousand identical spam messages. In a couple of hours. Resulting in:

-rw-rw---- 1 [username] mail 108385920 May 29 13:18 [nameoftheinbox]

Also known as one bigass inbox. Check the screenie. Anybody knows someone at bookrepublic.com? You or your network is hacked, dumbass, and that lamer is abusing my own root address for delivering 13647 identical spam messages to a mailbox I rarely read. Ah well.