It resulted from a typo. I was writing a domain
registration system for an ISP and, during some
debugging, forgot to use the --no-act command line
flag and ended up registering aoeu.com for real.
Since it was so easy to type, I kept it.
The letters A O E U are the first four characters of the left hand on a Dvorak keyboard, which is the layout I use.
One of my favourite introductions, and the one that convinced my kids to use it, is The Dvorak Zine. It includes history, how to use it for different operating systems, and is a fun read.
If you've come here, it's probably because someone filled out a form with an @aoeu.com address. Just like folks using the traditional QWERTY keyboard tend to lie and use @asdf.com addresses because it's easy to type (all letters on the left hand), users of the Dvorak keyboard do this too, resulting in @aoeu.com.
If you really do need to create a fake email address, you should use the officially blessed example addresses, which are guarenteed to be used by no one. These include
These domains are specifically reserved for examples. See RFC-2606 for other test and example domains.
Yes, someone owns aoeu.com, asdf.com, nobody.com, none.com, and other frequently 'fake' email domains. Please don't abuse the legitimate owners of those domains -- use the example.{com,org,net} domains instead.