Thanks to Phil Britt who confirms the online issue has been solved and that the deal is again available online as well as over the phone.
NB you have to select the power modem and not the basic, for the code to work.
Update: thanks to tranter, deal still works over the phone if you mention the "free modem for new customers" offer
Deal expiry says end of July
I signed up for Aussie Broadband a couple of days ago and got the WHIRLY10 discount (about $60).
A few days later, and it's I could've gotten a month free (about $80).
Tonight they email me and I could've saved $149! :S
For those who would like a modem instead of a month free (in the other deal right now), you can get a free premium modem valued at $149 if you include the code at sign up. ($15 shipping for regular delivery)
It's a Netcomm NF18ACV
(Thanks to Porthos for reminding me to write what modem it was)
Pre-configured and if there are any issues, they will handle it, I assume (as opposed to buying it elsewhere and having to deal with that store, for a saving of $15 or so).
I don't think this is targeted, the email looks like a generic offer and has an expiry date.
More background if needed:
I filled out the application form a few times (without actually finishing the process) over a couple of days. Today is about 4 or 5 days later.