It seems that LinuxAus is the single constant user of a .conf.au donain, and auDA rep Jo Lim said “future plans for [the] domains would be examined later this year”.
The report also says that “one option would be to switch off both [conf.au & info.au] domains and encourage existing users to register using other domains. An alternative approach would be to grant the rights to sell [domains] to a commercial registrar”
Neither option would be ideal; the first would cost us the lots, and who knows how well the domains would do under sale?
Anyway, if things go “blip” later this year, now you know why. This was linked to by Lxer.