What to do about brief text messages with misspelling?

>> I'd bite the bullet, use the PBL, and get your Asian clients to fix their
>> configurations.  It's one time pain for long term benefit all around.
>
> I agree with John, but a compromise might be to whitelist those clients
> instead of getting them to change their configurations to use some
> form of SMTP authentication.

There's also the hoary hack of POP-before-SMTP, a dynamic whitelist of 
hosts that have recently authenticated for POP or IMAP.  That used to be 
very popular before SMTP AUTH, and you can probably still find code for 
popular MTAs to do it.

R's,
John